11 days late for my period, could I be pregnant?

I am 11 days late for my period which is very unusual as am normally like clockwork. On my due date, after wiping myself there was a tiny spot of blood so umed i was coming on but nothing. From the next day and still, i am suffering from very tender , headaches, bloating, back ache, felling queasy, using the loo alot more and heavy discharge. I tuk 2 hpt last week and they were negative, went the doctors 4 pee test still neg, what are the chances i am pregnant and if not whats wrong with me? Just to add i am not under any stress at all no change in diet, exercise etc ..