Could it be possible?

So my expected period was due yesterday. I took a FRER too early (last Sunday) and then again on Monday and till they were both negative (we have been trying for 8 months so I just struggle waiting at this point). But I didn’t get my period on sat and so far no sign of it today. I took a dollar store test yesterday afternoon and it was negative. I know it’s probably just a late period but has anyone not been able to get a positive dollar store test but actually still been pregnant?

I have wasted so much money on FRER like... in the 100’s of dollars over the past 8 months. I am scared to go buy another one just to have it be negative and the disappointment that comes with that.