I was diagnosed by my Psychiatrist. I see my therapist to help with coping skills, talking about issues that come up etc. I think it's okay to question the diagnosis, but if you feel that it fits for you and you feel that the symptoms you bring up to your therapist are "dismissed" it may be wise to see another therapist. Perhaps you could find a therapist that specializes with mood disorders? You could even ask your P-doc for a referral.
As far as helping with the hypomania, avoiding caffeine helps me, exercising helps, I usually can't do yoga when I'm hypomanic because I want to yell HURRY UP in the class and that's frowned on LOL! Try to think of something that normally calms you. Being around my horse does that for me. Meds are about 60% of managing the illness for me the other 40% is therapy, eating well, exercising,etc.