South Africa will probably be really good for you right now if your having troubles with friends etc at home. The people you are going with you don't know now but after a month out there together you'll probably grow really close and you'll meet a load of new people as well. And you would have shared the same amazing experience (and it will be an amazing experience by the way, I'd kill to go to Africa!) and your friends back here will seem silly, pathetic and immature when you get back!
Don't decide not to go, that could be the worst thing! Just embrace it, and try to let go of the negative attitude when your there and enjoy it, that's the best way to attract other people towards you. I know it's easier said than done and you can't always just forget what's going on back here, but hopefully being in a completely different environment will help, and it will open your eyes to the world a bit.
Have fun, I'm sure you will have an amazing time XX