You could have bipolar disorder. However, you really haven't given us much to work off of (in terms of your symptoms and current life situation). I would take a look at
this article, and if you can relate to the symptoms and signs, then perhaps you should see a doctor and talk about it. There are also some mild forms of bipolar disorder (cyclothymia, for example:
x)
If you can't relate to any symptoms or signs, most likely you are just acting normal.