Dont know whats wrong with me

I feel so deflated. So i was supposed to ovulate according to the app on the 11th, fertile window 8th-13th - we had sex most days from the 5th. It was my first month using the ovulation tests ordered cheap ones didnt quite get how that works - kept getting a line but not as dark as test line. Anyway - according to app AF due in 4 days. So i did a pregnancy test yesterday and i got a faint positive. This morning i got a negative. This afternoon i started bleeding. Pretty sure its AF. But whats really strange is tgat would mean only a 24 day cycle - that never happens - im usually between 28-30 days. Whats going on? 🙁🙁🙁🙁