Pregnancy test help!!

This might be the wrong group. Has anyone ever gotten a positive digital test then negative regular tests afterwards? I have been breastfeeding and haven’t had a period since I was pregnant. (10 months postpartum) I took a cheapie on Sunday with first morning pee got a faint positive. I took a digital on Monday in the middle of the day, it read not pregnant. Took a digital test Tuesday with first morning urine and it said pregnant. Took a test this morning and evening both negative. Not sure what this means.