So, for this weekend, I decided to get myself out and be happy. Just like a couple of you advised. 
On Friday, I helped a co-worker throw a surprise birthday party for her friend. It was a nice feeling. The friend had no idea that anyone knew it was her birthday, so she was really really surprised.
Yesterday, my roommate for this semester and her friend invited me over to play some card games, and instead of rejecting their offer like I always do, I accepted. It turned out better than I thought it would. I had a good time.
I know it's not much, but I feel pretty good about it. And I thought I'd share it.