Regretting unprotected sex

The thing keeping me up at night and causing me panic attacks upon waking is the fear of contracting a disease from my monster. Funny, when things were going good it didn't even cross my mind. I guess the whole we'll be together forever thing is all I could think about. We'll, while at the doctor the other day getting klonopin to help deal with the anxiety, I also got orders for blood work testing for HIV and HepC. I got so upset at the thought of finding out my worst fears (positive test) that I literally got heart palpitations and started sweating. I can't go through with it until after the holidays. I need to mentally prepare. But the fear and regret is eating me alive. Anyone else able to relate or have any advice at all? I know he was promiscuous (despite what he claims), had OW, has access to lots of willing women, so I can only imagine the number of women he's slept with. Uggghh