I was wondering if have a bad cold or flu, or antibiotics can prevent you from staying hard?

Hello im 22 yrs old, my girlfriend and I had wednesday and i kept it up, and i have had no previous signs that i couldn't keep it up. Then thursday i got really sick and took an antibiotic called amoxacillin. I took 2 500 mg of them on thursday and thursday afternoon. then i started taking one and then took liquid motrin for my headaches. i then stopped taking them staurday. I felt better but my nose was still congested. So we tried to have again and i got a ***** but as soon as i stopped it went away. So i was wondering if i should be concered or what i should do? I have never had this problem and its been about 4 days without taking medicen and it still happens. So if anyone can help it will be greatly appreciated thank you.