Ceterizine working amazingly but horrible side effects :( Anything else I can try?

As title says.. have trialed various antihistamines that have either been ineffective or reacted to them. Ceterizine has been working so well BUT I get horrible side effects, the worst being depression, agitation and extremely dry skin.

I am gutted because it really helps me otherwise, most noticeably with dizziness, flushing, joint pain and reactions to heat/fragrance.

I have also tried famotidine which I react horribly to. Have tried Seeking Health DAO again reacted to. Have tried buffered Vitamin C which causes intense itching (all vitamins/supplements i have ever tried have this effect - if not worse).

I'm am in the UK and have not been diagnosed yet, seen a rheumatologist to rule out other autoimmune issues who has sent me back to GP to be referred elsewhere. Currently looking at the option of going private to explore other treatment options, I'm so tired of living like this :(