Hey there
Your bowel is used to lots of bulk, and isn't getting any now.
Avocados are FULL of fibre and fat, and very low in net carbs. Eat them - I try to get in at least a half an avocado a day. Also, take metamucil or psyllium husk in water. This should move things along.
And I don't know if you've given up caffeine - IMHO, it's not necessary to give up caffeine - caffeine can stimulate your bowel. So can hot liquids. When I need a little "ooomph" in the morning, I drink a cup of hot tea down as fast as I can without burning myself.