Has anyone ever tested negative but at a later date had a positive?

I had some bleeding on Monday (for around 2 days, mostly light with slight heavy one morning).

I was due my period on Thursday/Friday (assumed my bleeding at the start of the week was my period at first then learnt it could be potential implantation bleeding. My period is always 5-6 days usually).

For the last 4 days or so I’ve been feeling so sick, the thought of some foods make my stomach curl. I cannot stop peeing! every sip of drink, I’m back on the toilet. I’ve also had lower back ache. I still feel very much so today. But my boobs are fine?

I tested yesterday and had a negative test, I tested this morning and had a negative test.

I see so many women testing way before their period is due and getting a positive. I’m a day after my period and it’s a BFN. Is it safe to say I’m out this month or is there any glimmer of hope that it could still turn in to a positive?