Could the tests be wrong? Why am I spotting like this? Help

I’ve been having brown spotting for a week now(on/off). I was supposed to get my period on the 21st yesterday (it’s midnight now so today is 22nd) so I’m now a day late. We did it on my fertile days and even before/after. I don’t know if these test are faulty or not I used the Clinical Guard HCG pregnancy test strips I’ve taken 4 and they are all negative.. the most recent reviews on them said that they aren’t sensitive or just faulty while they have positives from other brands (I bought it from Amazon). I’ve been constantly using the bathroom fir 2 weeks and I’ve been feeling bloated the past week. I’m trying to get pregnant this is my first time and my husband is getting bad thoughts now if I’m infertile and stuff even though this is our first time trying.. we are quiet young so I shouldn’t have a problem getting pregnant.. hopefully so.

only when I was younger my period was irregular, but it has been consistent for a long while now (a few years?) but I’m not getting it so far even though I’m due for it..