If I went to a new psychiatrist and didn't tell him/her anything about my past history, they wouldn't think I had much wrong with me at all. They'd tell me to get some good sleep, eat my veggies, and have a good time. A doctor shouldn't just diagnose you solely on what they've seen or not seen. A person's history is important.

If you believe your depression symptoms were severe at any time in the past, describe them to your current psychiatrist in detail. Ditto for any manic or hypomanic symptoms.

Just because a person is not currently mentally unwell doesn't necessarily take away a mental health diagnosis.

As for Cyclothymia, that is a serious mental health disorder. If it wasn't, it wouldn't be in the DSM-5. Prolonged minor to moderate mood episodes are not "nothing". If one qualifies for that diagnosis, medications are often necessary.