Feeling left out

Hi, I’m a 20 year old college student and I live with my two cats as emotional support animals and two of my teammates from my college sport. They are best friends and very close, I have pretty bad depression sometimes, get anxious when overwhelmed, and have some heavy trauma that one day I will work through. Anyway, I love them both to death and I’m very sad one of them is graduating in may so she will move out. I worry that the other roommate won’t want to live with me anymore since I’m not really fun and sometimes am very quiet. I don’t drink really at all I’m on medicine I can’t, I don’t really like parties, I never feel comfortable going out and they always go out all the time. In the beginning of the year I tried really hard, I drove them to parties and they would go off together and then eventually I would just sit in my car till 2 or 3am when they were ready to go home. They sometimes whisper talk about things in the house, and they are always comforting one another. I’m sorry I’m not really sure if I have a question or something but I’m just struggling feeling alone, and it makes me really sad when they go out and I don’t feel as bonded with them as the friends they party with. They do support and care about me I just worry I’m too much of a burden to deal with sometimes. I go to college far away from my family, don’t have friends from home, and they make up a big part of my support system, I just worry so much about losing them by being too sad and not fun.