What Medications Effect Pregnancy Test?

My husband and I had sex while I was ovulating. A week later I was in a car accident and was prescribed pain killers and muscle relaxers. They did a urine pregnancy test at the emergency room, which was negative. A week later, I got a yeast infection (which I've never had before) and I know this is a sign of pregnancy, so I took another test at home. It was negative. I then used a vaginal cream and vaginal sapistory. My period is now 11 days late and it has never been even one day late before. I am having all the symptoms of pregnancy such as nausea, cravings, cramping, moodiness, fatigue (maybe some of those are from the car accident?). I took two more pregnancy tests and they are both negative! But I'm worried that they may say negative because of all the medication I've taken lately??