Light brown bleeding on first day of “missed” period

I was supposed to start my period today and I do have some light bleeding, but it is very light brown and barely spotting. Normally I start in full heavy bleeding on day 1! But I took a pregnancy test and it was negative. My body has been acting weird coming up to this period, the type of cramping I was experiencing felt different than my usual. I just hate the fact that even though I am bleeding and have a negative test, my brain still wants to cling to the fact that I could be pregnant.