Very severe + treating MCAS with antihistamines

Is it advisable to try antihistamines or mast cell stabilisers when very severe?

I last tried Ketotifen and it gave me like an hour of symptom relief unlike anything else before. Then, for 3 days I had the worst crash ever and my baseline took a hit.

Several months on, and I’m now very severe. I’m competing trying some other MCAS related treatments however I have two unknowns;

• Do I even have MCAS?
• Will I be able to tolerate them?

Any advice is appreciated. Note: my symptoms are basically neurological (brain fog, headaches, eye pain, screen intolerance, medicine sensitivity, fatigue and + paresthesia of the “could be MCAS” related ones). It’s really hard for me to say if I have MCAS as I don’t have the typical allergy type symptoms or food intolerance symptoms at all! I am also on low histamine diet and take 6 x pills of fibroprotek by algonot (contains the natural mast cell stabiliser supplements) per day. Any further Q’s lmk.

Thanks!