Sudden extremely heavy blood flow?

Now, two days ago I had sever pains that came in waves. I thought it was my period because it came from that area, but the pain was enough to make me cry and worry a little. The fact that the cramps lasted for several minutes, all about the same pain as well, made me worry more.

I bled very little that day, which I found funny.

Now, I've always had irregular periods and heavy ones too, but this one is different.

I have to use the biggest tampon that can soak up the most blood, but I'm starting to have to change them every hour to hour and a half. Even when I'm sleeping. I'll wake up and rush to the bathroom to change.

Yesterday and today, I've had no cramps. I can't feel when the tampon is getting full today. What is worrying me the most is the fact; I've always felt the blood leaving my body. I can feel it. This time around, there's no sign of that.

My mother-in-law says there's no need to worry, my body is playing catch-up. This is the first period I've had in a couple of months, but I've been through catch-up before. It has never been this bad. Ever. Now I'm dizzy, light headed, pale, weak and I'm feeling really sick.

Has anyone else had this happen to them? If you have and went to the doctor, what did they say?