I am so sorry for your loss. Grief is its' own animal. I am sure you will suffer from guilt as well, "what if I....why did I not....." It can go on and on. If loving your brother would have been enough to keep him with you, he would still be here, however, It was demons that were in his head that took him. IT WAS NOT YOUR FAULT!!!! always remember that. Cry whenever you need to and talk it out when ever you need to. This is not something that will "go away" But in time it will be tolerable. Grief effects your whole self, holistically, body, mind and spirit. Grief counseling is not only helpful but a necessity. Maybe consider an anti-depressant or anti-anixety or both while you are still in school.
I am so sorry this has happened, reach out to others on the internet, there are many sites of people who have suffered the same fate and connecting with someone who knows what you are going through will give you strength.
Take care of yourself....as you WILL carry on.