Hi. I Had Sex With Someone Other Than My Boyfriend

Hi. I had sex with someone other than my boyfriend unprotected. The other guy also has a girlfriend and I'm pretty sure he has unprotected sex with her too. I was actually on my period at that time is was really light plus I have an IUD in place. Now my vagina is itchy it isn't normally itchy. I still have my period this was a couple days ago. I am unsure what is wrong with me. Can't tell if it's a yeast infection because I see no discharge due to me having my period.