One of the things I find really helps and I really enjoy doing when i'm in a bad mood is going for a walk or a jog. It doesn't matter what the weather, if its cold, wear a jumper! I've always liked the rain but if you don't like it then fair enough if you skip out on going running in the pouring rain! I just think even if you don't feel like it. Most of the time you will feel better if you go for a walk outside. As they say, the fresh air will do you good!