The TV is your friend!!! When I was pregnant with the twins and chasing a 4 and 2 year old, I planted them in front of the TV as much as possible. It won't kill them, seriously.
Also, put your son in a room where he can play safely unattended and stretch yourself across the escape route/doorway with a pillow. Then YOU take a nap while he plays. If he tries to crawl across you to get out, it'll wake you up.
Ask your DH if he can make dinner at night. It's just a temporary thing. Reassure him he won't be doing it forever.
Hang in there. I know how tired you are and I feel for you. Big hugs and energetic thoughts coming your way.
" I object to violence because when it appears to do good, the good is only temporary; the evil it does is permanent." Mahatma Gandhi
"This is the ultimate weakness of violence: It multiplies evil and violence in the universe. It doesn't solve any problems." Martin Luther King, Jr.