my son has been constipated for two days and i have given him stool softeners to try to help him i just switched him to Vyvance on thanksgiving, he has thrown up his food since he has been stopped up and i'm worried it hs somehting to do with this new med. He has never been sick a day in his life other than the adhd and of course he is manic because of the adhd meds please help i'm scared to death