Help?

So I'm scared I might have an sti but it's not really likely. I use Summer's <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> and normally it causes me to discharge more after I use it, but lately it kind of burns/itches when I pee, I had sex and it was kind of hard because I wasn't wet at all but that's kind of how I like it anyway. I'm just curious as to what it could be. I don't think it's an sti bc he had sex with a virgin before and he was a virgin hisself so I was just his 2nd partner and the girl didn't have anything so I don't think he could've given me anything but I'm really confused bc it like burns/itches to pee. Please help