Questionable... Period, maybe?

Ok guys. So, I don't know whether to be concerned or just wait it out. I was suppose to start my period last Saturday, the 17. And didn't. Making me 8 days late today. And since the Wednesday before, the 14th, i have woke up everyday sick to my stomach. Some days it goes away with food others food makes it worse. I have been having BM problems, heartburn like crazy, and my sex drive has been through the roof. This morning, I got up about 8am went to the bathroom, and started what i think is my period. Only problem is, from 8-11 i have gone through 4 super plus tampons and have taken 2 doses of Mydol (4 pills) to relieve the pain/cramps i am having and it just literally only blanketed the pain making it manageable. I constantly feel like i have to pee and i am absolutely exhausted. I feel like i could close my eyes and not wake up for a longtime. At 11 i had the bleeding down and i did not need to put a tampon back in. I have been wearing a pad and there is barely anything there. Since Saturday, i have taken 5 pregnancy tests all saying negative, is it still possible? I am so lost and really need the advice! Please give input!

Update: after changing my pad, i noticed that after a few hours, there was spotting like a red orange color. But when i wipe after i pee, there is barely anything on the paper... I put a tampon in, just in case, so I could go to bed, but it just feels weird and uncomfortable. I am slightly more concerned. Anyone have any clue what the crap MIGHT be happening?