Suggestions welcome

So I’m struggling and determined to help myself.
I’ve been told I’ve entered perimenopause and have blamed symptoms on that but I just feel so awful and wonder if there’s more.

Histamine is driving me wild. Shampoos, hand lotions, carrier bag handles (wild one) food. I feel like anything can set me off.
I’ve got hives, skin itches and this god awful feeling of something crawling on me. My skin stings and I’m so ashamed of how it looks.
It gets triggered after a hot bath but I seem to think going from cold to warm triggers it as well. Like climbing into bed. (No bugs trust me I’m so paranoid with the skin crawling thing) exercise trigger a warm red flush type rash over me as well.
Heart palpitations which seem to have decreased with my vitamin d and magnesium (would they help?)
heavy bleeding and low ferritin
Bone pain around ankles wrist and elbows
Diarrhea
Been told I have asthma due to my chronic cough but I always seem to have sinus issues
I’ve got so many symptoms that I can’t think what to list. I’m so fed up of not knowing what perimenopause and something else.
MCAS fits except I have high blood pressure? It never seems to go down. I’m on two meds and it’s doing nothing.
I get light headed and feel like I’m low but it never reflects on the monitor. Sitting here now with that hangover dirty feeling and weird lips, headache and warm. For no reason. Light headed in waves.

Just need a bit of advice on if MCAS would be worth looking into. I know no one can diagnose me so not asking for that. I’m pretty sure I fit except the constant high blood pressure.
Uk based as well if anyone has advice on how to approach a reluctant doctor who wants to diagnose everyone with stress and anxiety

Thanks for any help.