Had a change in my stools and the frequency of bowel movements. Used to have a bowel movement just about everyday,now it is much less frequent and a lot less than normal amount of stool in each movement. Almost feel constipated sometimes, I feel like I need to have a bowel movement but little to nothing comes out when I go. My stools have also changed to a darker brown and became somewhat harder. Havent changed my diet and always drink a lot of liquids. Also experiencing a pulsating or twitch sensation in my anus. Usually only happens when I'm laying down and not moving. Any idea what this could be? Thank you for your time