COVID-19 drastically changed the world in March of 2020 with all the worldwide lockdowns and safety precautions set out by the CDC, and before we knew it, the Food and Drug Administration (FDA) issued the first emergency use authorization (EUA) for what would be known as the first COVID-19 vaccine to be distributed in the U.S. in December of 2020 -- the Pfizer vaccine. As we all know, it takes several years to develop a vaccine. So, of course, everyone is concerned about its safety and side effects.

Despite the unknowns of how it can affect the human body in the long run, I still decided to get vaccinated.

Here's my (detailed) experience with it to help you get an idea of what you can expect if and when you get the vaccine!

A registered nurse administered the first dose of the vaccine at approximately 4pm on a Friday afternoon. About an hour after it was administered, I was a little light headed, began to feel weak, and had a soreness at the injection site on my arm.

Two hours after I received the vaccine, my light headedness and weakness persisted. However, my arm soreness worsened. I began to develop restricted movement of my left arm (the arm that the vaccine was injected into). I also felt as if I was being deprived of energy. All I wanted to do was sleep, and I felt as if I needed to sleep for a couple of days. I also got the chills during this hour. This happened while I was eating a spicy meal. I didn't know what it was at first, because I was like, "Why am I feeling cold all of a sudden? Shouldn't I be feeling warm and starting to develop a runny nose from this spicy meal that I'm eating?" Then out of nowhere, it felt as if there was an air conditioner on full-blast right in front of me! It lasted for a good twenty seconds or so, before the imaginary air conditioner went away and I was back to feeling just a normal sense of being cold, which then lasted for a few minutes. I also experienced slight joint pain in my back, as well as mild muscle aches in my right leg.

Three hours after I got the vaccine, my restricted arm movement persisted, while my light headedness, weakness, and energy deprivation all began to worsen. I also started to develop a headache.

By the fourth hour, I was fighting with all my might to stay awake. All of my symptoms from the previous hour persisted. My restricted arm movement persisted, and I was still light headed, weak, lacked energy, and my headache began to worsen even more. 8 pm is such an early time for me to go to bed, so I decided to watch a movie in my living room with my parents to pass the time, but I wasn't really watching.

By the fifth hour, 9pm, all of my symptoms from the previous hour persisted. However, the headache wasn't just like any normal headache. It had a distinct feel to it. It was concentrated on the left side of my head and the pressure was MUCH stronger than any headache that I had ever experienced before. So, I decided to call it a night, and I went to bed. It took awhile to actually fall asleep though, because the headache wouldn't go away, and I was experiencing slight joint pain again.

The next morning, Saturday morning, I didn't get out of bed until 10:30am, which is late for me. I'm so used to getting up and starting my day around 8 AM. I must've been really weak and felt the need to sleep in for me to feel healthy for the day. But honestly, I could've easily slept in for several more hours if I wanted to, because I felt as if I had absolutely no energy to physically get out of bed. Soon after waking, the severely painful headache had reappeared.

All throughout the day, the headache persisted (still very painful), I experienced slight joint pain every now and then, and I was fighting the urge of wanting to sleep -- making it hard for me to study and do my homework.

By the third day, Sunday, I was feeling half-way better. The joint pain didn't come back, and the headache and tiredness weren't so bothersome.

About a week later, the headache reappeared, and I developed a cold. I had a runny nose, and I couldn't stop sneezing.

Three weeks after my first dose was administered, I got the 2nd dose at around 12pm on a Wednesday. I felt the tiredness an hour later, along with soreness at the injection site.

Four hours later, I got the painful headache, and the tiredness worsened, but they weren't nearly as bad from my first dose. My arm also didn't have as much of a restricted movement compared to the first dose, because I had a cell biology lab earlier that afternoon and was moving my arm often.

The next day, Thursday, I only had a slight headache. The tiredness and the soreness at the injection site had resided.

However, by the third day, Friday, the side effects hit me pretty hard -- but still not as bad as the first dose. I still couldn't focus on school work due to the tiredness and painful headache, but at least it didn't last the entire day.

By the fourth day, Saturday, I was back to normal. However, a week later, the headache reappeared, and I developed a cold -- once again. The runny nose, and constant sneezing seemed weird to me -- the fact that it showed up a week after receiving the vaccine for both doses.

So how was Pfizer able to create, test, and distribute their COVID-19 vaccine in less than a year?

Because their approach to making the vaccine was a new way that has never been done before. It does not involve the growth of, or even the usage of, the actual virus itself.

Therefore, Pfizer did not undergo the months that it usually takes to grow a virus.

Instead of injecting people with the virus, they inject people with a part of COVID-19's genetic code. This is how they were able to develop their vaccine and start testing it in clinical trials only three months after the genetic sequence of the virus was shared. This is how they developed the vaccine in record time.

They take only the part of the code that instructs cells on how to make the virus's spike protein. It is then encoded into mRNA, and it is injected into the human body.

This will then instruct your "cells to make copies of the spike protein [that can be found on the actual virus] as if the cells had been infected by the coronavirus." The body will then have an immune response - learning about the virus, fighting it off, and protecting the body from getting sick with the virus if it were to come into contact with the actual virus.