I don't know for sure if I am or was pregnant but feel like I'm possibly having a miscarriage.. what r some tell take signs to look for, so I know whether I should head to the doctor??

Edit** I'm Soo close to my period start date, is why I'm slightly confused, but the last several days I've been extremely weak, nauseous (even vomited a couple times yesterday) to the point where I can't get out of bed, and I've had abdominal pain but just assumed it was because I haven't really eaten a full meal, just lite snacking here and there.. but I woke up this morning bleeding.

Not sure if I just started early or if my symptoms the last few days indicate something more.