I was thinking 'stress' too. I know many of us think we are pretty much unaffected by this virus situation, but yesterday out of the blue I had a huge black cloud descend.
Has this happened to you, gradually, over the weeks and is putting on your brave face stressing you so that your vulnerabilities (hives) has resurfaced? All subconsciously, without you realising just how stressed you are?
I've only had hives twice, on my legs and trunk and the itching is unbearable - I remember standing in the shower one night and pouring neat domestos onto my hands and rubbing it all over the blisters.
It stung like H*ll but the pain was such a relief after the itching it was worth it and I got to sleep that night, I didn't try it again and I'm NOT suggesting you try this BTW.
Anthistan does help but I couldn't find any bigger tubes either, although I didn't try Amazon - and I didn't contact the manufacturers, or even ask my pharmacist - all of which might be worth trying. Its a bit expensive to keep buying the standard tubes.
The airosol WaspEze also helped for short periods - but again expensive in large quantities. Try Amazon.
I must say, your GP doesn't sound very sympathetic. You need something stronger than paracetamol for the pain of the itching.