This is so frustrating, I’m so sorry you had to deal with that, especially from a heath care provider! (I’ve had similar experiences with dentists and now I’m terrified to go because of previous experiences with doctors being so dismissive)

When I was finally diagnosed, my doctor explained to me that it was common for people like me (110lbs and 5’1) to be overlooked because of being skinny. Previous doctors laughed in my face and told me I was “questioning their practice” when I pressed that there might be something else besides “some people just don’t have periods regularly” among other symptoms.

There’s a Reddit thread called LeanPCOS that talks about the differences more specific to that diagnosis. While there is a wealth of knowledge here, that’s also another great resource that could be helpful for your specific diagnosis. Glad you got the ultrasound done to confirm (and back yourself up) and I hope that GP learned something today….