Cyclothymia is a mild mood disorder...that sometime seen as a personality trait then the illness. People with cyclothymia have repetitive periods of mild depression followed by elevated moods.
Some people with this develop full blown bipolar disorder at some stage in their life... while others can or will have depression or severe mood disorders...
Some people say that cyclothyima is common amoung "creative and high acheiving people"
With the idea being that having cylothymia come up with new ideas during their brief high periods...
It's easy to look this disorder up on the web, but be careful with self diagnosis, alot of people who self diagnose actually get diagnosed with something completely different.
It's best to talk to your doctor and get the proper treatment and diagnosis.
Good luck, I hope this information helps.