Any other possibilities?

Olivia

Got 2 tracking apps,

1st app says that I’m 17 DPO and 3 days late.

2nd app says that I’m 12 DPO and af will due in 3 days.

Got mild cramps for 5 days now and I took pregnancy test today and it said negative. Are there any other possibilities why do i get mild cramps? I also got a bit nausea but no vomiting.