My Period pains are now like labour pains?

I gave birth nearly two years ago. For the last six months my period pains now feel like labour pains (all in my backside and completley crippling). Has this happened to anyone else and does anyone know if there is anything I can do to help? Labour was bad enough and it only lasted 4 hours. Now The pain is there for 3 to 4 days and I can't walk with it. I miss normal period pains, lol!