Can DH take DS for you for a few hours this afternoon so you can nap? I wish I had the answers for you but my DS was just the same at your DS's age. I know a 40 mins nap isn't enough but if we had a rough night I would sleep with him for both sleeps and just take it easy that day.

I find that I have to get a few hrs a week/fortnight to myself and that really helps... is that an option for you?