helpp pregnet ???

Paola

I has sex on the 3 of march I take my bc everyday at the same time. However I got put in antibiotics and pain killers such as rophamin, kenelog, methacarbomal, and idoprophen 800 for muscle pain and a uti. I am scared this reduced the effect of my pill. I have felt so nauseous since Monday . I had my last period last month on the 24-28 . Could I be pregnet if so when can I test.