Antibiotics & Birth Control—HELP!

The title says it all, but I’ll give you some backstory. I’m 21, I’ll be 22 in September, and I’ve been on birth control for 6 years. I’ve currently been battling to a sinus infection for 10 days now. I went to the doctor on day 6 and was prescribed a strong version of amoxicillin. That day & this morning, my S/O and I had [unprotected] sex, as we always do.

My sister calls me this evening to ask me how I’m feeling, and I told her better. We talked and gossiped like sisters do, and then she informed me that taking antibiotics can prevent your birth control from working. My heart stopped and shot up to my throat. I don’t get sick, EVER. So I’m never taking antibiotics or even going to a doctor really.

My question here is does anyone know how long you actually have to be on antibiotics before it interferes with your birth control? Or how high the risk would even be for me since I’ve been taking it for 6 years? Thanks in advance!

*please no negative commentary. My S/O are both very mature for our age, and we work hard everyday. I am not worried as I am sure this is the person I am supposed to be with*