As people have said said, change your diet. Eat high fiber foods in the morning such as beans and try some peanuts, peanut butter or other high fiber snacks a lunch. You'll be shitting in the evening in no time as long as you have a bit of exercise early in the day and plenty of water. Keep a bottle of water by your side all day at work and work on getting through it by the time you make your journey home. If all else fails have a SMALL glass of prune juice every evening when you get home. Also, try to get through at least two litters of water a day and cut back on coffee.
Being an opiate addict has thought me many things but beating life threatening constipation is may be my most valued. Also, here's a tip. Never eat fiber if you are taking opiates or are dehydrated to any degree, trust me on that.
ugh I was waiting for the bus today and then I felt DAT feeling in my gut... "FUCK YOU I WAS JUST INSIDE THE SCHOOL AND YOU HAVE TO ACT UP WHILE IM OUTSIDE?!?!" Half an hour later after coming out of the bathroom it felt like there was fire ants stabbing me with flaming mini knives and/or I felt like I ate 1000 ghost peppers