Is this my period or a chemical pregnancy?

My period was due Saturday 6/2. I started bleeding Sunday 6/3 and it was mostly just brown blood mixed in with my discharge. By Monday morning I noticed that I am bleeding much more heavily than usual and experiencing cramping and extremely sore boobs, which i never experience during my period. I bled through my tampon in 4hr when i usually dont change them until 8hr and thats only to avoid TSS, not because theyre full or leaking. I got home from work at 1130pm and took a shower at 1am and i was still bleeding heavily. I usually dont bleed much at night, if at all. Im not sure what may be going on. Possibly a chemical pregnancy? The blood doesnt seem to be very clotty though.