So, I've been on the pill for about 7 months now. This last week, I got a sinus infection, and was given antibiotics. I completely forgot that antibiotics can make the pill uneffective.

What are the chances I could get pregnant if I had taken the antibiotic for 2 days, and we had sex on the 15th? (I think I ovaluate around the 17th, so I'm really worried.)

Any help please?

I also don't know if I should tell my boyfriend about this. He gets worried so easily, and I don't wanna worry him if it turns out to be nothing. Idk. Any advise?

Ok, there is a chance, of course. Some girls have gotten pregnant even when they were taking the pill full time. But it doesn't do you any good to worry about it, even though it might seem impossible not to worry. Just wait until your period is a week late, and then take a test, ok? Keep us updated!
Hugs!