Pregnant or not???

So my period is 3 days late now. I am never late. Ever. Always on time with some spotting the day before. My boyfriend and I have been doing the “If it happens, that’s great! If not, no big deal” thing since I got my non-hormonal iud taken out.

I have taken three tests now and they all say negative! I don’t have any symptoms that my period is going to start and I’m flipping out.

Does anyone have any advice?

Update:

So I slipped and fell on ice yesterday and started to spot a bit. Then this morning, nothing. I’m so confused but because I started to spot yesterday, I think, if I was pregnant I lost it...