Hiya hun, what is your situation? Would you be ok having a baby now?
To be honest, I'm from a biology background (have a PhD in molecular biology) and antibiotics tend to have the affect of rendering the pill ineffective for as long as you take them and beyond.
If this happens, the negative feedback that the hormones in the pill exert on your pituitary hormones (the ones that cause ovulation), will be removed. It is therefore possible that you could get a surge in pituitary hormones released and they could cause ovulation (normally on the bog-standard contraceptice pill, you won't ovulate).
So I guess it depends on your situation. it is possible that you could have concieved, but then again, you may have been fortunate (depends how you look at it) and not concieved.
If it was me and I really wasn't in a situation to be pregnant, I'd get the morning after pill (I think it can be prescribed up to 72 hours after unprotected sex). If it would be ok to be pregnant, then wait and see what happens at the end of the month.
I'm sorry if this isn't what you want to hear, but I want you to have all the information so you can be prepared. The only thing is, I'm not sure about the specific brand of pill you are on. It could be different.
You should also continue to use condoms for the rest of your current pill packet if you've had antibiotics during this cycle. They affect the whole cycle and you are still at risk of getting pregnant.
I really hope this helps you, and that everything works out the way you want it.
Let us know how you get on.
xxxxx