Part of the reason you have low self esteem because you isolate yourself. Try to make friends and hangout. It's really easy to make friends in college. From writing clubs to cosplaying, there are so many things to do. Find out what your interests are and then join clubs that are based on that. Try interacting with other classmates, you already have one thing in common, a class. Isolating yourself isn't going to help you meet new people or help your self esteem. As a matter of face, many colleges have therapist/counselor students can see free of charge. It's free and private.