Implantation bleeding or PMS

I need some help. I dont know if it was my period or implantation bleeding. My period was late for 6 days a week later I started to cramp when I wipe i saw light pink then brown discharge. It got heavier and i started to cramp bad. Next day I bleed with no cramping. The two days i spotted light pink with no cramping. My last day I spotted light pink and then night time came light bleeding went away. But I cramp pretty intense and i bleed heavy. I bleed for 4 days. But this time I bleed 2 days one heavy the other day kinda light not as heavy. My period is usually 5 to 6 days. I just found it very weird. I took a pregnancy test when i knew my period was not coming and it was negative. Any ladies experience this before? Im so confused. My son mention to me TWO times that theres a Baby in my belly and that is CUTE