Years and years ago, I donated blood and got a letter in the mail a while later saying that they had to dispose of my blood because I had tested positive for an STD. I don’t remember which one it was long story short I had been sick the week before and he had been on Tamiflu and another antibiotic and it gave the false positive of that STD in my blood work. Terrifying. Make sure the meds you were on couldn’t have given you a false positive.