There is a lot of misinformation about MCAS online. Id avoid most of the online support groups that are not linked to legit or official sources. There are a lot of self diagnosed people in those who are giving out bad advice and misinformation.

Mayo clinic Rochester also does not generally treat MCAS specifically and seems to focus on Mastocytosis only which is very different than MCAS.

Symptoms of MCAS are similar or the same as so many other conditions it can be hard to get that diagnosis.

I am a Connective tissue disorder EDS and MCAS patient who meets the diagnostic criteria.
Its common for those 3 to be linked together.

I would start out by seeing your primary care and discussing your symptoms. Id ask to get some baseline tryptase levels done over the course of a few months to show what your baseline normally is. Draw those only when you arent having symptoms or at least not having a flare up or reaction.
Then see about a referral to allergy and immunology.
Medications like Zyrtec, Pepcid AC can be helpful. There are others as well but you need to work with someone familiar with this condition.

Avoiding triggers is really the key. Its all about management.

Try to avoid high histamine foods , alcohols, etc..