First Day at College

Our 16 year old son has put himself through a difficult day.  First day at college and he got too stressed and walked out.  We have only just found this out as we were expecting him back home about 5.30pm but he has been wondering about for hours without calling us and then finally gets to his nana's around 9pm!!  At least we know he is safe but its so worrying.  We just don't think he is ready for college yet.  His anxiety is so high at the moment with anger and ourbursts and his OCD is making him so tired.  Just not sure how to help him.