What Causes Light Menstrual Flow And Bloody Clotting Discharges With Bloating?

I am having light menstrual flow than usual. I dont know if this is implantation bleeding it's my 3rd day already and usually i have cramps 1-3 days of my mens, and this period has no cramps only on the first day. I have bloody and clotty discharges. Could this be oligomenorrhea? pregancy? I'd been stressing about this lately. I feel bloated, no tender breast, nausea or vomiting. Help..