Depression. On my studies. i!

I am 18 engineering student.i and my bestfriend broke up in 2014..we were bestfriends since 12 years. I had insecurities of losing him but i never told him..once an instance i was angry seeing him and other girl pictures which he himself sent me..we were texting at that moment.i shouted and sort of teased him in very bad way.he felt bad and he walked away..at that moment i was studying intermediate in hostel so i couldn't talk to him properly since there were no connections like phone etc.i missed him every moment..i used to come home on weekends just to talk to him but he just dint wanted to talk to me...then the next year i shifted to his clg still he chose not to talk...its been two years now but he considers me as a stranger..i miss him..i am in depression..its like my family is getting victimized to my changing moods and am very terribly angry person who loses my mind while am angry..i couldnt concentrate my studies ..i really want to move on and concentrate on my studies..i