Im 17 years old and my boyfriend is 18. Weve been together for a year and a half and we moved in together almost four months ago. Ever since we started living together our sex life has been non-stop and we have unprotected sex at least 3-4 a week. We aren't ttc, but I also wouldnt be devestated if I got pregnant. We dont use condoms, birth control, etc, but I still start my period every month and every pregnancy test I've taken has been negative.

Everything ive read or have been told suggests that getting pregnant is one the easiest things in the world, and that the slightest bit of cum will achieve it. I know that isn't the case but I also cant help but to be disappointed every time that stupid stick gives me the result I dont want to see. Does it just take time? Could there be an underlying issue? Should I be concerned, or is this just the way it goes?