Spending quality time just by yourself is not the worst thing, if you can enjoy it!
Yes, I just did that. Spending time by myself, and no other people who accompany me. And thats a great move, you know?
We have to gives a chance to cheer up ourself. Ya for example go to bookstore, you can buy books anything you like (if you have a money), and just read it (if you not have some money).
So throw away your badmood. Its not good for your life. Life is too simple to follow your badmood. Cheer your mood up with something positive activity.
If your friends doesn't want to accompany you, you can walk by yourself. Its a great, trust me. Everybody need a refreshment just for yourself. Enjoy it, feel it, and smile :).
Thats my way to cheer up myself if I got a badmood. And tonight I feel soooo good though Im alone.