TTC - Reply Back plz lol

okay so me and my bf are TTC. We have unprotected sex all the time ‼️ so recently i missed my period for about 17 days i thought i was pregnant (super excited) i kept reading google and different mom posts may people were saying they didn’t get a BFP until 3 months due to low levels. Sadly i got my period July 8 😩 so ready to try again has anybody missed their period for that long and randomly just gets their period? what did i do wrong ? how do i know when i’m ovulating? could their be problems within us ?