Most people need a certain amount of alone time per week to be able to function normally and not blow up at the person nearest to you. Depending on your level on the scale of introvert to extrovert, you may need more or less time to spend with yourself. Alone time doesn't mean you need to be isolated from people, it just means time in which you are not having to exert yourself socially. Maybe not speaking more than an order to a waitress for a few hours. The best part is that you get to chose how you spend this time with yourself.
1. Walk somewhere for coffee
If you usually get your morning coffee fix at home, sipping it while surrounded by your roommates, try finding a cafe that you can walk to on your own. You get a peaceful walk to yourself, as well as being able to drink your beverage without constant conversation.
2. Go on a run
You can run 3 miles, 1 mile, a half a mile, 0.2 miles...it doesn't matter! Running gives you some time to see new areas of your surroundings, and turn your music up as loud as you want to sprint your stresses away.
3. Find a hidden gem
Exploring on your own is a great way to run into new things. You don't have to worry about what other people want to do, leaving you to wander wherever you desire and try new things that you might like.
4. Go grocery shopping
There is no better excuse to be alone than doing a chore like this. Actually, it can be really satisfying to go pick out food for yourself to have that week, as well as fulfilling a task on your own.
5. Take yourself to lunch/dessert
You can go wherever sounds good to YOU and try something new on the menu. Bring a computer, book, or journal to get some things done in the meantime.
6. Shop for a new candle
Go sniff around for a scent makeover of your space.
7. Cook yourself a fun meal or snack
If you have the kitchen to yourself for a little, spend the time to teach yourself how to make something new that you can enjoy and incorporate as a meal more often.
This list is mostly just to get you started on understanding how easy, yet important, it is to do things by yourself every so often. There are a thousand ways to do this — you can really do anything you want alone as long as you don't let social norms wriggle their way in!