Being able to study abroad is a once in a lifetime experience, that I would recommend to anyone. However, there are definitely some challenges that come with living in a foreign country without your friends or family for a semester.
1. Time change.
Keeping in contact with friends and family is hard when you are so busy, but if you are in a country in a completely different time zone it makes it near impossible. When I wake up in the morning, everyone is in the middle of their sleep. When I go to bed, everyone's days are just beginning.
2. Having school work.
It's very hard to be school-focused when you are concentrated on what country you will be flying to next weekend. Despite the fact that your classes will most likely be easier than at home, you still have to try and put some effort in.
3. Spending money.
Everything is so expensive. Some cities are more expensive than others but you will find yourself spending thousands of dollars over the course of the semester if you are travelling a lot. Make sure you budget for this.
4. Staying active.
Sure, there are gyms in other countries, but finding the motivation to go everyday is a lot harder. You are in a completely new place and doing different things so making it to the gym probably won't be high on your to-do list.
5. Language barriers.
This won't apply for every country, but I am studying in Italy and went with no knowledge of the Italian language. I am slowly learning but trying to get around takes a lot of pointing at things and google translate.
6. Different paces of life.
The United States is a very unique place. Everyone is in a rush and does things as efficiently as possible. Most countries in Europe are not like this and it can be very frustrating. This takes a while to get used to.
7. Going out.
At school, usually people go out some Thursdays, Fridays, and Saturdays. In European countries (and particularly Italy), the big nights are Tuesday and Thursday, along with Friday and Saturday. It is exhausting.
8. Having FOMO.
It hasn't been as bad as I expected, but it is sad seeing your friends at school doing things together when you can't be with them.
Despite these little negatives, it is still an experience everyone should have. These complaints of mine are nothing compared to all of the adventures you will have abroad!