The advice from Caryopteris is really good, you should definitely go and see a medical professional.
You should also monitor your diet to see if there is any food that could be contributing to your colon problems.
As far as fibre goes, there are two types of fibre, soluble and insoluble. Both types of fibre can relieve constipation however insoluble fibre can often make bloating, discomfort and pain worse. Bran and corn fibre are a couple of examples of insoluble fibre.
Studies with IBS-constipation predominant patients found that moderate amounts (5g/day) of partially hydrolyzed gaur gum (PHGG), which is an insoluble fibre, reduced symptoms. It might be a good idea to try guar gum.
I have a lot of information on diet management and natural treatments for IBS on my website. But once again, you should go to a medical professional who can see what might be going on.
I think you are having a serious bout of constipation. You would be smart to have a colonoscopy or barium enema to find out what your colon looks like right now. Chronic constipation can cause all sorts of problems, so knowing the cause now before other problems, like diverticulosis, complicates things would be smart. You might have something benign but problematic like splenic flexure syndrome, or a colon that is longer than normal and all twisted up, which is slowing things down.
Otherwise you should reserve strong laxatives like Dulcolax for times when you are that bad, but try to avoid getting that bad. Something that might help or might not is Metamucil. You would need to take it every day with enough water and see how that does. If it makes things soft and moves things along, great. If it makes things to large and hard, then it's not helping. In that case you might try MiraLax. Hopefully that will do the trick for you.
Be sure you are not eating processed and fried foods too much. Avoid cheese and dairy and see if that helps. Eat lots of vegetables, including leafy greens. Avoid only those that cause too much gas to work for you. Eat fruit too, and leave the skin on apples and chew well.