You need to be more specific. Lots of fiber? You might consider wheat bread fiber. It is not. Please elaborate. You MUST have a BM each day. Here is my suggestion.
1. First thing when you wake up drink a tall glass of warm water with 1/2 lemon sqeezed into it, 1/8 teaspoon Sea Salt and 1 tblsp raw apple cider vinegar. Warm means heat it up in a pan, not microwave, till it is warm to your elbow.
2. 30 minutes later or more eat breakfast. Avoid breads, milk, and junk food.
3. buy some milled flaxseed and take 2 tablespoons with breakfast and 2 with dinner. It would also help to take 1-2 tablspoons of olive oil or flaxseed oil before bed nightly.