MAJOR TMI

So I had sex with two different guys within a week. I was drinking a little both times and it was so heated and in the moment so we didn’t use condoms. Neither of them are very experienced and they said they both get checked and didn’t have STDs or anything like that. The second guy had a very large penis, bigger than I’d ever had before. Since my vagina has been in a lot of pain and extremely swollen. Since then it has become itchy and sore. I think I might have a yeast infection because that night I slept with jean shorts on that were super tight. But it’s excruciatingly painful and I need some advice because I’ve never had a yeast infection before and I’m scared I caught an STD. Please help I’m so embarrassed and ashamed.