ok so on April 26th, I spotted a little. but I just thought AF was here. then the 27th and 28th I…

ok so on April 26th, I spotted a little. but I just thought AF was here. then the 27th and 28th I bled normally, but then that was it. my periods normally last 6 to 7 days and this time it only lasted about 3 days. i took a pregnancy test on may 17th and it was negative. then yesterday I spotted a little. and my ovia app still said I still had 4 days until my expected period. which is weird because it's always been very accurate until lately. now today I've been bleeding (quite a bit) and I'm hurting sooooo bad. my cramps don't usually bother me, but today has been awful. I'm just curious if I could possibly be pregnant, and it's just implantation bleeding, if I was pregnant and didn't know, and miscarried, or its something else. please help.