I know the problem. Our cat has only got to see me putting my shoes on and he thinks its time to go to the 'Stabby Man'

I have some Feliway spray that I use in his carrier which calms him down once he's in there. I have to catch him first before I put my shoes on, then he wails for a while before the spray starts working. By the time we get to the vet he's usually well laid back. Its the catching him that's the hardest part. Perhaps one of the Feliway diffusers in your house might help.

Feliway here on Amazon

Feliway