Drunk and Unprotected

I started university 3 weeks ago and I hate it.. I feel like my world is falling apart and I feel incredibly alone.. I moved to a big city and so many things just don't feel right.. 
I've been struggling a lot and I don't usually drink; however last night I got incredibly drunk and had unprotected sex with my boyfriend.. I'm not copping with anything and I don't want to turn into a complete mess, someone help.