You won't be able to know or even show symptoms of pregnancy until a missed period. So in the next 4 weeks u will know, it's impossible to know after 4 days.
I have advice. :) If you're not you need to buy the condoms or get on birth control. My BFF had her first baby at 19. It's been a difficult road financially for her. BC is free on most insurance plans now. If you're on your parents plan and feel funny about them knowing then you can go to a clinic like planned parenthood or other community resource and confidentially get very low cost meds. Take responsibility right away so you're not scared next month too. Good luck.
Thanks so much for the advice. I know that we should of used condoms but it kinda just happened. And with other medications I'm on I can't take birthcontrol.