HELPP!!

So the other day me and my boyfriend were getting a bit you know and then for the first time I sucked his dick, I've never done anything like this before but now I'm worried that I caught and sti. I was supposed to come on my period 3 days ago, I have all the feeling that I'm going to come on but my vagina just feels like it's burning when you touch it with anything. I really want to know what is wrong with me.