Having fear with people. Less socialnow!

Hi dr my age is 19 yrs and i am studying for neet I am living in a hostel. I was living in another hostel where i have friends of class 11 i was living happily but when i reached in 12 i changed my hostel due to food problem Here there is no any single person who is studying in 12 with coaching Every one here is either in 11 or 12 passed out o can not talk to anyone because i am living in a room and study myself as i missed 2 months so i started studying myself then i joined online course there i study and score good marks but here there is change in my behaviour i did not talk to anyone so i am lonely living in room no outside going reason and i develop a phobia when I see lot of people in mess specially in groups where everyone is talking but i am not i became feared and depressed i can not change my hostel due to agreement signed by the hostel Please tell me how i can bring my previous nature  Now 3 months left then will be home. When i was at home they told me y'r less socialnow