Next step?

I hooked up with somebody i just met this morning around 1. i have them on facebook. We had sex but during all of a sudden he went soft. It was really awkward so i got off of them and was gonna play with it and get it up again, he said he needed some time and i was like uh okay. Thinking he was uncomfortable. I got dressed and i asked him why he was done and he said he couldn't go anymore & i asked if he had finished and he said yes. So this means it happened inside of me and im not on birth control. I feel really disgusted and betrayed. Anyways if i get a plan b tomorrow and take it will it work? Do i ask him to pay for half of it? What if he says no? How do i begin the conversation? Im feeling really nervous and as a single mom of 2 already i cant have another. I know im gonna get judgement but i wasnt expecting that to happen.