STD From Oral

Hey, I have a question. I was in a relationship that started to become toxic. I was never good enough anymore and all he wanted was to be physical. We never had sex, that’s something I want to save for marriage and he was the same way. But he kept pushing for me to do oral on him. I didn’t want to but from the pressure I gave in. I did it 3 different times, the first only lasting like 10 seconds, 2nd time like 20 seconds, and the 3rd time like 25/30 seconds, He never finished in my mouth and I rinsed my mouth out with mouthwash after. It was all very gross to me. Ever since then I’m very paranoid about an STD. I have had some minor health problems in the past with just getting sick a lot with a low immune system but I don’t think I have any symptoms for an STD. I’m not in a place where I can get test so that’s why I’m jumping on here to ask and get some peace of mind. Please help