Sounds very similar to my endo pain, accompanied with a heavy period can make you feel pretty miserable!
When it comes on strong, I'm doubled over in pain for many hours, and have to stay in bed for a day.
Did you come off birth control after bubs? I found after birth my endo has gotten worse (it was great for 5 years after a lap) and put it down to being off the pill, which really helps to keep endo at bay (lessens your symptoms and the disease from spreading)
Hope it gradually just gets better for you, it sounds pretty debilitating xxx