Three days ago I had unprotected sex for just about 30 seconds to a minute at most. It was also eight days from when my fertile window is supposed to start, a week after my Follicular Cycle started, and four days after my period ended. You know as well as I know that regular cum and even pre cum can contain sperm and can be easily transferred. There was no regular cum involved during vaginal penetration, but there might have been pre cum. I'm not on any form of birth control at the moment. Now I'm 24 days shy from when my period is supposed to start and I'm worried about it not coming. Granted this app is pretty accurate when it comes to my cycle and I know if I am pregnant I want to have an abortion, because of the situation I'm in. I have no way of paying for it and the only way I can pay for Plan B is with a gift card, however they say you should take it within three days after unprotected sex for the best chance of it working and today is that day. I can't tell my family even as an adult because of how my situation is with them, and so I really have nobody to turn to and help me out financially with getting an abortion if necessary minus the guy I did it with as he's my boyfriend, but he doesn't think I should worry about it however agrees I should get on birth control eventually. I truthfully don't know what to do and just need help pretty quickly. Do you think I should get Plan B or just wait and see what happens or something like that. Any advice or opinions would be welcomed.

Update: I didn't get Plan B, but should I still be worried?