Kind of TMI.....but I'm worried!

According to Glow, I am right in the middle of my red fertile period. My boyfriend came over and spent the whole day with me, and we mostly cuddled and watched netflix, but we had sex twice. The first time was with a condom, so no issue. But when we did it the second time, things just got a little confused. We were naked and maintained genital contact (without penetration) for about 10 mins or so, "dry humping" I guess. He eventually decided to go ahead and start vaginal sex (we use the withdrawal method whenever we don't use condoms). The in/out thrusts were very VERY slow and drawn out, and he only did a handful of them before he suddenly pulled out. Usually, it takes him about five solid minutes of sex to cum, so this was incredibly unexpected for me! I guess the foreplay buildup was just too much. But anyways, since he came so unexpectedly, he managed to pull out in time but unfortunately had no time to aim, and it shot all over the exterior of my vagina. I'm freaking out, I know that sperm is referred to as "swimmers" for a reason. Please help! Any advice???? What are the chances of pregnancy from that???