Welcome to the disorder! Kidding aside, your terror of unnecessary medication and your therapist's skepticism are well-founded. I have no qualifications beyond my own longtime personal experience with bipolar disorder.

You described a single episode of mania that was bad enough to put you in the hospital, then having doctors diagnose you as bipolar after a subsequent depression, and adding 'a ton of medications to your cocktail.' Were you referring to the medications that they gave you during the manic episode, or were you taking medications prior to the initial manic episode? Doctors do seem to have a tendency to throw an entire spectrum expensive chemicals at patients simultaneously in hope of achieving stability with minimal side effects (then, maybe, sling some more expensive chemicals in hope of alleviating the side effects).

Many of the drugs are essentially toxic (lithium eventually reduces your kidney function, Depakote can kill you, Zyprexa can make you eat yourself into diabetes, etc. and there is big money in these drugs, especially the new ones. I've gone into pdoc's offices that had sample boxes of one particular cutting-edge high-priced psychotropic or other arranged in sight like merchandise, and wonder of wonders, that's the very prescription I ended up with. You do the math. So yeah, be really careful with your diagnosis, and what you are being prescribed as a result. Having said this, bipolar disorder is dangerous enough that I'll take a high dose of Depakote, an anticonvulsant potentially harmful enough (potentially lethal) to carry an FDA Black Box warning (imagine how hard the makers of Depakote lobbied against that) that keeps me dull and overweight (it's also reported to cause hair loss; some miracle of vanity has spared me that so far) every night. The punch line is that it doesn't even fully suppress the disease; I still cycle and have mixed states and all nature of lunacy, but I'm too afraid of the unfettered disease even to stop Depakote and try something else (I've already tried everything else, and, unlike your doctors, I don't believe in stacking suppressant psychotropics when one doesn't do the trick). So ask a lot of questions. Read a lot. Your therapist is skeptical for a reason. You'll know if the diagnosis is genuine if the disease returns. In the meantime, be careful. Don't tell your new boyfriend until you are sure that you're in it for the long term (both the disease and the relationship).

Don't underestimate the power and the permanence of the stigma surrounding mental illness. Going out of your mind once in a while and then being written off for the rest of your life by the ones closest to you hasn't felt good. I think it may have given me a significant anger problem, but I'm sure my doctor has an expensive drug for that.