What are the chances?

I've been reading about the early signs of pregnancy online (awful idea, I know) and its freaking me out. 
Here's the deal: I take my bc at the same time every night within one hour. My so and I have sex 3ish times a week and he always! pulls out. What are the chances I could actually get pregnant? I have been feeling tired and getting headaches lately. I just had my period, it was perfectly regular and normal just like it always is. 
Someone please tell me I'm just letting the internet freak me out and that it is highly unlikely that I could actually be pregnant.