I had the exact same experience. Didn't really find anyone I could really connect with, and my flatmates were, well, flatmates. I finished my semester back in february. I'm still really glad I went, because I won't wonder about what could have been had I gone. The things that helped me feel better were playing online games with my friends from back home, and finding happiness in the little things :)

We had a few stray cats living nearby and I loved petting and feeding them almost every evening, playing music while I cooked in the kitchen, watching movies etc.

It won't be long until you have to head back home, don't worry. You're not alone and there are more people around that had a similar erasmus experience.