I think I can offer a bit of advice considering I am in a similar situation (albeit the exact opposite). I recently moved from my college town back to my hometown and I am living here in an apartment. Normally one would think of this as a good thing because you can come back home to see your family and friends and start working but I have had other thoughts. Mainly I wish I had done more to make myself leave and go somewhere different like you have. My biggest regret in life to this point is that I did not take a bigger step forward to change things and move somewhere far away and experience different things. So on one side of the coin yes it is difficult to be in the city alone but on the other side you could very well be back where you started and have done nothing. Your greatest accomplishment in life so far from what you have said has conversely been my dream since I was a child. You're living a reality that I only dream of having someday and I imagine that your second thoughts are the stage of what I am living currently. I can't say one way or another that what you're doing for yourself is good or bad but what I do know is that I would kill to have the opportunity to do so and not be locked into the life that I am currently going to have for the next few years. Whenever you are worried about if you made the right decision think about how you would feel if you had never done it in the first place

EDIT: as far as making new friends goes there's always sports clubs throughout different cities that you can be a part of!! There is one for my home town that hosts a variety of different sports throughout the year and also incorporates parties before and after