looking for advice!

Basically I had my period from 19th march - 24th march, I then started bleeding again a week later (31st) and I'm still bleeding now, the cramps from the first period were that bad I was reduced to tears and the period I'm having now I'm not really getting cramps it's more of a sharp stabbing pain, since the first period ended I've been waking up with really bad headaches that disappear throughout the day and come back again when I wake up, any idea why I'm having 2 periods in the same month and is it worth booking a doctor's appointment because I've never had this before? (sorry for the long post)