So I am supposed to start my period in about a week. I have been spotting on my pantyliner for the past two days with dull cramps in my lower stomach. Which is weird because I usually start my period the exact time I'm supposed to. The cramps go away and don't hurt like my period cramps do. I am sexually actively and had sex on my most fertile day with no birth control or condom. Is this implantation bleeding or just old blood? I've never had this happen before.