Why is this happening?

[CPHB2021]

Hi all, I’d be really grateful if anyone has any idea why this keeps happening. Twice now I’ve had one day of getting positive tests, but by the next day they are negative and then I go on to get AF, very delayed. I thought that I must keep having chemical pregnancies but would I only show as pregnant for literally a few hours if that was happening? Could still breastfeeding have something to do with it? I’m really confused as to what and why it’s happening. I would love if anyone had an idea!

Which tests are you using?
the Asda’s own ones are awful for giving false positives!

What tests are you using and are you tracking ovulation?

I used one step strips. They showed the positives, though they were negative at first. I ran out of them and used some boots own brand strips which were negative. They were a higher mui than the one step. I didn’t use OPK’s but have ordered some for my next cycle. AF still hadn’t showed!