White and painful spots at back of throat. Had unprotected oral sex. Did I get an STD?

Please help, I have white, painful spots at the back of my throat after I gave my boyfriend a blowjob. He told me many times that he s never been with anyone else than me before, so I thought that he can t possibly have any STDs when he s a virgin like me. But still after giving him unprotected oral sex my throat started to hurt for a week and I did it on him again and then my throat hurt more than ever, the back of my throat was red at first but then it became more white and lifeless as the white spots appeared, and my throat hurts very much and it s very panful to swallow , it especially hurts where the white spots are. However, I started taking some medicine and it feels better now, it s less painful to swallow again, but I really need to know what this sickness is. I got a fever a little while ago and my head hurt all the time and it was affecting my ears as well. All my energy is gone and my throat hurts constantly. Did I get an STD? how is it possible to get an STD when both partners are virgins? Please help me Dear Doctors, I m so scared :(