Hi there!

I think it would be beneficial to track your moods. I use an online tracker from www.medhelp.org
Then set up an appointment with your primary doctor and try get a referal to see a psychiatrist. I know it has stigma's attached, but you can pretty much keep all of it under wraps from friends, family and work.
Tracking your moods will help your doctor to pick up a pattern.

I hope you are able to reach out for help, and get some relief from the rollercoaster