Food Sits On Stomach

for the last several weeks, I have not been able to go to the bathroom. At first, I tried over-the-counter laxitives, then I went to the Dr. He gave me a prescription of mirlax; after consuming this I had a movement for 2 days. I am backing up sooo much that a visible bolus can be seen in my ab area. I went back to the Dr. Again, and was told to drink citicel and was given another prescriptive laxitive - an suggestions? I am so miserable and I do have a history of problems w/ my inestines, but not so w/ my stomach. After consuming food, it will sit in my stomach for hours. I am not overweight 32 yr. Old, 5'5 1/2" tall 127lbs. And I am very active. Help.