When you say the FAA doesn't care: the FAA doesn't assume that you were misdiagnosed and thus isn't interested in any assertions of an incorrect diagnoses. The FAA does care about the diagnosis. Again: the medication assigned is always of concern with respect to the effects of the medication, but the chief concern is always the condition for which the medication was prescribed.

The FAA is not known for accepting arguments of misdiagnosis. If an incorrect diagnosis occurs, the FAA will require documentation showing that one is in compliance with medical standards, or standards acceptable for a waiver (eg, special issuance). Simply discontinuing the medication does not address the original diagnosed condition, or the reason for which the medication was prescribed.

You indicated that you're working with your psychiatrist to gain favorable documentation, in order to reapply. You also indicated that this is a fresh case. It sounds like your case had been submitted to the FAA for consideration. You may need to wait until the FAA has either responded with a resolution, or a request for more information (almost certainly the case).

You should step through this under the direction of specialists who will guide your specific case, as all such cases are decided not on general or generic criteria, but on an individual basis. The resource most often recommended here, and which I recommend, is Aviation Medicine Advisory Service (AMAS). They'll have a phone or email consultation, and will propose a course of action (and fee associated with). AMAS is not composed of AME's, but a different class of physicians who advise; most of them have been military flight surgeons and/or have FAA experience. They work with you on your case specifically, advising on what you'll need for your application process, and in the case of special issuances, will submit everything as a packet with a recommendation letter. The initial consultation is the place where you can discuss your specific diagnoses, the implication of a misdiagnosis, subsequent documentation (what you'll. need, from whom you'll need it, the time frame, the order, and quite possibly considerations or additional testing or documentation that you may not be aware of, yet).