Advice on how to be taken seriously?

Been told I likely have a mood disorder of some kind by my therapist of several years. And I agree with him.

The symptoms manifested at around age 15, peaked pretty bad at 16 and was in psychosis for several months.

And over the years I have had major ups and downs, that have usually been overlooked as "Oh you're doing really well at the moment!" And then "what happened? Whyre you down hill?".

My current therapist has been the first to pick up on it (and several bipolar friends). But now I'm struggling to be listened to enough by other professionals to actually figure it out. For many years, and still now, I've been told my up and downs are "normal"- no matter how detailed I explain the ups and downs- though granted the MH system in my country is notoriously fucked up and dismissive.

How can I lay it all out to a professional to be taken seriously without sounding nuts? Lmao

(Quick TW)

There's a family history of bipolar, my symptoms started at 15-16, I have weeks to months long manic and depressive episodes, episodes can include psychosis, anti-depressants send me off the fucking rails, in several manic episodes I have spent or given away thousands of dollars or engaged in risky behaviours (walks alone at night in sketchy areas, reckless sexual behaviours, severe SH or alcohol consumption out of boredom) and have also gone minorly psychotic (hallucinating nearly everyday, barely sleeping, and delusions that I'm being stalked or that I'm a god and cannot be killed...and tried to prove it..).

Which...is not normal lmao. So how can you out-line that enough to be listened to properly without looking like I'm nuts or seeking some kind of outcome- because I'm not, I just know that..whatever it is, is not fucking normal.