Cramping and bleeding

I am 2 weeks pp and have had a fairly easy recovery. I didn't even have cramping or pain right after delivery. And my bleeding has been very light since about day 4. This morning I woke up with fairly intense cramping and heavier bleeding, including a couple clots about the size of ping pong balls. The cramps are intense enough that I don't really feel up to doing anything, I want to just lay down in the fetal position. Is this normal 2 weeks pp or should I be concerned? I've heard that bleeding should not get heavier or increase at this point, but it has.