Feeling Lost, Please Help!

So my boyfriend and I had sex last week and afterwards he pulled out before he ejaculated and there was no condom. He was 100% he didn't come inside me. We ended realising it was inside me and eventually we got it the condom outbid me within the hour, but I'm worried about being pregnant.
I don't know how to get the day after pill and I'm not on birth control and my period was supposed to come yesterday. 
I desperately need advice, I'm petrified. What do I do?