"I just have to sit for about 20 minutes and strain REAL hard to get anything out.."
Never do this. You will get hemorrhoids and/or anal fissures and/or hernias. Let your digestive system use peristalsis muscles to eliminate, otherwise they will atrophy like your other muscles. Plus your food needs to stay in your system for a certain period of time to get digested and absorbed. Why do you insist on forcing a bowel movement?
Stop all dairy including anything with milk and that kefir stuff. Stop anything with gluten including all wheat products.
Do the liver flush. 3 or more would be better.
Stop focusing on supplements and "tricks". Your diet is #1 here. Eat live enzymes, like a whole papaya for lunch instead of enzyme pills.
Is there any reason why you would not have enough stomach acid? Are you bulimic?