He thinks I have an STD

So like 3 weeks ago I hooked up with this guy and we didn’t use a condom. I knew I was clean because he was the only person I hooked up with since I last got tested. After he hooked up with me maybe a week later he hooked up with another girl. I only knew this because yesterday he messaged me out of the blue, keeping in mind we haven’t talked since we hooked up, he asked me if I had an STD. I told him no and asked why and he said “because I hooked up with this girl after I hooked up with you and she said she thinks she has gonorrhea because of peeing frequently, sore throat, and fever” at this point I’m just in awe that he thinks it’s from me because I told him I was clean. So I asked him if he hooked up with anyone else and if she hooked up with anyone else and he said no. So now I’m just thinking well this bitch it overreacting then because I know I don’t have anything but he’s still trying to put the blame on me. I have a test today and I know it’ll come back clean and I just want to tell him off after I get the results because this is just ridiculous. How should I tell him??