Antibiotics and birth control?? Could I have ovulated???

So I am on Loestrin and got a sinus infection, my dr gave me amoxicillin for 10 days. We've had sex twice this week, the last time being the day before yesterday. I felt my ovaries aching a bit (thought it was all in my head) and now today I had what looked like ewcm! Was it semen??? We already have a 9 month old, not planning #2 for another year so this would be a surprise.