Heartwrenching

We have had some really difficult days with Carson. He has been so unhappy and having awful crying spells. He will cry for hours at a time and we have no idea why. We havent been able to figure it out until yesterday. This is why its so heartwrenching having a child that is non verbal because its always a guessing game. Carson cant tell us when hes hungry, tired or hurting. He had strep throat over winter break which was so awful for him. A week after that is when he started these crying fits and we had no idea what was wrong so we brought him to the doctor and the doctor said his ears and throat looked fine and the only thing he could think of was that the antibiotic was hurting his stomach. We took him off the antibiotic and gave him some prescribed gas drops and he seemed all better. Well then a few days ago it all started all over again and finally we realized that he has been constipated because we started him on soy milk and he loves the stuff and drink a lot of it!!!! I'm so relieved that we finally realized what the problem was but its been so heartwrenching for us to see him so miserable and we dont know what to do for him. He has had both Billy and I in tears over the past few days because we both just want to make him happy and its so hard to see him so upset :(