Within The Past Week I Have Noticed Changes In My

Within the past week I have noticed changes in my bowel movements. First of all I'm on methadone and have been for three years. I have been slowly detoxing, and over the last year I have went from 70 miligrams per day to 15 miligrams per day. The methadone causes me to be constipated regularly. But over the past week I have been going more frequently and my stool has been accompanied with a mucous that smells worse than normal. My diet is not the best, and hasn't been for a long time. But my diets has not changed lately other than I have been eating fruit and yogurt for breakfast rather than the cereal and donuts I was eating. Is this serious? Will it pass?