Need advice

Me and my boyfriend had sex for the first time (the 16th) a week after I started getting unusual hunger cravings... I started getting hungry every time I see food and this is very weird for me because I usely eat very little 
A week and a half later (from the day we had sex) i got a pregnancy test and it came out negative 
I was supposed to start my period Friday and it's Sunday now it is also very unusual that the app is wrong its been right for about 6 months straight 
When I didn't get my period the Friday i got another pregnancy test the Saturday but it still came out negative 
I don't know what to do I told my boyfriend about it and he doesn't know what to do we are both still young (17) and not ready to have a baby... My mom thinks i am on my period and I don't know what to think or do??? He didn't even cum in me...