STD/STI? Help please

I had unprotected sex with a guy back in early November. And something cryptic he said to me the other day has me worried/panicked that he thinks he gave me an STD/STI. I don’t have any weird discharge or bad smells, and I had blood work done back in January to check my iron levels. If I had something wouldn’t it have popped up in my blood work in January? And is it possible to have something but not have any weird discharge or bad smells?