Why is my body like this!

I usually have the the most excruciating cramps on my period. I’ve been to the point where I get nauseous and throw up. sometimes I feel like my motor skills just shut down and I can barely move. Pills barely help, I’ve tried yoga heating pads, eating right, etc and I just can’t escape these symptoms. But oddly this last period cycle I just had was the exact opposite I felt no cramps at all not even a little bit. But the weird part also is that my period lasted nine days! it was very light for the first couple days. My period always lasts about four days so I was confused... I’m glad I got to get a break this time but I can’t come to grips of why this happened...