It sounds like you have a constipation issue. Very common. No, your stomach isn't damaged. But you can improve this situation. Your diet is one avenue to take. Eating more fruit really helps as does fiber. Glad you are taking a probiotic. My son had major constipation chronically and they had him start drinking a cup of dark grape juice daily. It has helped He also will take a stool softener as needed His pediatrician told us to. So, perhaps for one to two times a week, he takes the stool softener. Lastly, my best advice is to drink extra liquid. Think of your colon as a water slide. You need water to move the waste through. That it is big and bulky is part of constipation. All of the things I've mentioned should help. https://www.webmd.com/digestive-disorders/constipation-relief-tips