The nap thing is very normal----my twins sometimes sleep for a long time and sometimes for a few short minutes.
he could be going through a growth spurt.Fionn has done the same,sleeping literally all day.Also you have to remember, they will have off days like we do,its just that they cant tell you about it. I know it hurts you when you feel you have upset them, but he needs to get used to being away from you sometimes, if there was an emergency and you neeed to go somewhere he has to get comfortable with someone else looking after him.dont worry you are still being a good mum