2am everyday

At 2am everyday for the past three night I have woken up with the worst cramps and have to go number 2. It last for about 15 minutes usually I am lucky if I go at all. Why does this have to happen in the middle of the night. I take Metamucil and get over 35g of fiber from veggies and fruit a day and drink tons of water. So annoyed. It disrupts otherwise perfect sleep. I always have to get out of bed and lay on the couch so not to disturb my husband with runs to the bathroom for 10 minutes. Help!!!