ttc after depo

Hi ladies.

I'm about to finish up my depo shot (12 weeks is up middle of next week) ive just got this app so obviously it's a bit hard to know how accurate it is cause I'm not currently getting periods while on depo. Ive only done one 12 week shot but have heard it can take up to a year for ovulation to come back but ive also been getting positive otk results when app says i should be ovulating. Very confused! Can the depo affect the test? Also, did any of you fall quickly after stopping depo?