@glowworm,
In your first post you say say you have feelings that are "traumatic", "unpleasant" and "isolating". I agree that "mental illness" is culturally defined. The label doesn't matter. This is making you unhappy. This is something you should address.
I am sorry about what happened the last time you had treatment. They clearly failed to understand your needs or to treat you well. I still think that you should talk to someone now.
Things will be much better now that you are an adult. No psychologist can make "life altering decisions" without your consent (and no good psychologist will even try). As an adult, if you don't agree with your therapist, you can walk out and find someone who respects you.
There are excellent therapists out there. I encourage you to find one. I have found that most therapists start by asking you what you want. You can simply schedule a one hour meeting and talk to a therapist... and you can ask him questions. If you don't want medicine, or if you are just wary of medicine, tell them up front.
Don't let experiences in your childhood get in the way of you being happy as an adult.