What could it be?

I don’t think I’m allergic to condom because I’ve used it as my form of protection for years- same brand and everything. A month ago, I used a new kind & later my vagina was itching & sore. I bought a monistat & the cream helped the itching go away. Last night, I used the condom that I’ve always used & again, I had itching down there. Last night was the first time I had sex since about 3 weeks ago. During those 3 weeks, I didn’t have itching or anything until last night. What can it be that’s causing it? I was also wet so I don’t think it could be that I was irritated.

Also, it doesn’t burn nor produce any discharge. Just itches.