Not sure what’s happening…. Help!

15 DPO and after 2.5 days of very faint positives, my E@H strips came back negative this morning. First response and clear blue still shows a faint positive but I’m not really sure what’s going on since E@H looked negative and those had a faint line up until yesterday afternoon. Feel like I’m just sitting here with the same mild cramping I’ve had the last 3 days but now I’m waiting for my period to show up cause I feel like it might have been a chemical pregnancy? My period was supposed to show up yesterday at the very latest (between the apps that I use, it was supposed to show up somewhere Wednesday-Saturday and today is Sunday). Any advice would be appreciated!! This was our first month

TTC so I’m not really sure what to expect or what this means 😬