Sadly these moments can happen from time to time, I've been there too and it's important to know that you're not alone.
Lots of people handle this differently. Sometimes if I feel lonely or without anyone to talk to I watch a good TV show, I can relate to characters easy and usually shows with a lot of dialogue such as Suits or House of Cards can keep me very entertained and give me social satisfaction without socialising (weird, right?). I guess for yourself I would recommend finding something that makes you happy and can keep you busy.
You mention that you're not close to your family so you don't speak to them, have you tried looking at that the other way around? Do you feel that maybe you're not close to your family because you don't speak to them?
Lots of people do exactly what you're doing now and go straight from undergrad to postgrad. Maybe you feel now that a gap year would have been nice, but you're already on your way to your masters to the best thing you can do is keep your chin up and look only forward and not backward. Think of all the great opportunities you'll get and the satisfaction of completing your Masters!
TSR is a good location to talk to and meet new people. Forums are usually great for that. Perhaps there's student groups on the same course as you that you could join? Any games groups? Study groups? Perhaps even campus-related activities. Even outside of education there could be local things for you to join in on such as small clubs.