Oh Michelle, I hope it’s just a bit of spotting and cramping because your period would be now. I think they call it a breakthrough. It can be 100% normal to spot this early. Try not worry too much, it could make things worse (easier said than done I know). Test again tomorrow and the next day, keep an eye on the lines. If they are stil good by Friday I would have thought it would be ok. Got everything crossed for you.
Got everything crossed for you too mrs mummy, maybe you did ovulate a little later.
Hope you feel more with it soon FTale.