I think its the cyclical nature of your moods that makes me think that it could be Bipolar 2. In Bipolar 2 you USUALLY have more downs that ups and the ups are less serious than in Bipolar 1. Also something to think about, I've seen Bipolar described in terms of three facets of your experience: MOOD, ENERGY and COGNITION. If they are all elevated, it is mania or hypomania. If they are all down, it is depression. Do you notice yourself being mentally sharper, and having more energy, in addition to being happier when you are on one of your upswings? The answer might help to answer your question.