Firstly, Portals, that you are feeling invalidated. I don't know if I have any concrete advice about what to do about it... basically I have told only a few people that I trust to understand and have not told those I don't trust to understand -- or at least somehow try. Education on the topic can help, but only if they're willing to learn, you know?
You say you've been off meds in the past... are you on them now though? As for applying for disability -- yeah, it can feel daunting to tackle those sorts of things -- there are other threads where folks talk about how they deal with it, and hopefully some with experience in that will pipe up here too...