Great for you that you are thinking of taking steps toward improved mental health!
I'd certainly not tell my new therapist that I'd been diagnosed with bi-polar. Neither would I seek initial help from a psychiatrist. I would seek the services of a psychologist.
At some point in treatment when I was deluged by stress my psychologist referred me to a psychiatrist for an evaluation for meds. Well, as you know, if you come to a psychiatrist with a complaint of anxiety, depression, or the likes, the psychiatrist will most likely, probably certainly, hand you a prescrition. I mean, why then did you come to him/her? right?
Anyway, I went to this psychiatrist. She seemed really understanding of what I was saying to her, and she diagnosed me with I-can't-remember-what, maybe manic depression, and prescribed lithium!
I went back to my psychologist and reported on the psychiatric visit. She felt the psychiatrist had misdiagnosed me! My psychologist was saying this based on knowing me for 4 years, and the psychiatrist had only "known" me for a mere 45 minutes before arriving at her diagnosis! The lithium did not work out for me. I had trials of a host of different meds, all of which failed to help me feel better. I suffered more side effects than benefits. In the end I got off all of the meds and got onto a good nutritional program. That seems to help a lot.