Idk what to do

What does it mean if my vagina is swollen and painfully itchy? Is this a yeast infection or an STD or something else? I’ve never had this problem or any other problems like it before and I don’t know what to do. I just got off my last period a few days ago and my boyfriend and I had sex last night for the first time in a couple of weeks. Could either of those have anything to do with it? Looking to fix this problem ASAP 🤕😣