This really concerns my 3 and a half year old son. He was ill with a cough and a cold for 2 weeks and that was about 4 weeks ago, he then had a week were he was ok then he came down again with a nasty cough and was on antibiotics for a week. he is better now. My son is mildly autistic which is why i have nt been able to potty train him yet, but that is orrying me is that over the last few weeks or so, i have noticed he has very big gaps of having a dry nappy, he doesnt seem to be passing water very often, this doesnt happen everyday, but at least a couple of days a week or maybe more for example today his nappy was wet this morning when i changed it about 10am, tonight he has gone to be bed and hasnt passed water since this morning, and he has been drinking the normal amount. he isnt in pain and doesnt happen every day, but this is really worying me, i did ask the nurse and she just told me to hurry up and potty train him, but i cant see how that has anything to do with it? he is not at all distressed by this at all. what could ne wrong with him,is this something medical?