Worried Boyfriend

Hello. Im a very paranoid boyfriend..And I want to feel better so maybe you guys can help. My girlfriend is on birth control and we usually use a condom. She was on her placebos last week and we had sex saturday night, the last day of her placebos, but we didnt use a condom and I came inside of her. The next morning she took an ecp and her regular birth control pill because she started her regular pills that morning.

What worries me is, why did she take the ecp. She wont tell me except that she says im so paranoid that she did it for me so I wouldnt worry. I asked her if its because she missed a pill and she said no.

So even if she missed a pill, what are the chances of her being pregnant since she took the ecp just a few hours after we had sex? She just finished her period that afternoon before we had sex, and now today she said she bled a little more and that really worries me.