If you're constipated and haven't been able to poop then you should try drinking some prune juice or eating prunes.
Cranberry Juice and Cranberries if consumed enough can sometimes help relieve constipation and if all else fails you can purchase an enema kit and give yourself an enema using warm water and soap and the Enema will surely make you poop and fast so be prepared to get to the toilet soon after.
You'll hold the soapy solution in your anus for awhile and then release it into the toilet once the pressure builds up.
It does work cause I've had to use enema on myself before.