it is important to go slowly in the transition between to different diet .
you might need more fiber in your meals. try grounded flax seed mixed in your meal like salads .
eat more fruit which contain great amount of fibers as well.
also winter time if sometime harder on the digestive system when eating mosty raw.
try 3 tables spoon of olive oil and the juice of 1/2 lemon before going to bed and first thing in the morning.
definetly more oils (olive, coco, sesame) with meal.
in ayurveda we would call it vata imbalance. constipation is one of the predominant symptom.
maybe you need to build more heat in your digestive system.
ginger/lemon tea every morning, cayenne , powdered cinnamon and a tea spoon of honey,
do you feel nervous at all??? stressed??? lost ???introverted??? these feelings are often attached to this phisical issue.
some yoga practice as squatting for long period of time, and concentration on breathing , sitting and listening to your breath will calm these psychological effects.
be well
paix