Sharing Our Innermost Thoughts

I’m feelings very terrible, my classmates are not supportive and I feel as if I have no prior knowledge of any subject. I want to study well but always the question arises from where I should start. Im homesick and want to vent my feelings out but I somewhere feel everyone has their own problems and I’m burden to everyone. My roommate is very boastful. He tries to show that he knows everything and makes me feel bad about my poor knowledge about the subjects. How should I deal with it? What should I do to maintain my own sanity to stay calm ? And focus on myself ?