The best that you can do is try to ignore them and find other friends. You should try engaging in other activities either at college or in the local surrounding community to keep you busy (when you’re not working on classwork). If you try the latter, you’ll likely meet other people with whom you can spend time.
You might also contact your university counseling center. Counseling could help you with the loneliness and perhaps attend group therapy sessions for support.
Perhaps you didn’t know these “friends” as well as you thought you did. That’s fairly common in these types of settings (school, work, etc.). It takes a long time to truly know someone, to understand the nature of their character and their ability to be a quality friend. Sincere friends wouldn’t “suddenly” hate you and stop talking to you.
Not everyone is who they appear to be. In life, it’s good to know who you can trust and who you cannot. It’s an important lesson to learn. Perhaps you trusted these individuals too easily, when you shouldn’t have done so. Counseling would be a good place to analyze why these friendships didn’t last and help you to choose more wisely in the future. Good luck and please take care.