J.T.
I had severe HG with my first pregnancy, I was in the hospital 30+ times, one stay lasted a month, several days in ICU - I very nearly died... I weighed 84 pounds at about 16 weeks pregnant, a good 40 lbs under my pre-pregnancy weight. I had a PICC line inserted after many visits for fluids and meds, the PICC line was suppose to be a way for me to be at home, and receive TPN(continuous IV nutrition of several thousand calories per day). However, some mistakes were made in the OR, and we found out 11 days later that the PICC line was infected when it was inserted, and that infected set off a chain of events that nearly killed me and my unborn child. All that to say, I really do understand your misery. And it's awful, I really do feel for you. My 2nd and 3rd pregnancies I had way more than the "normal" morning sickness, lost a lot of weight, several ER visits, but nothing like the first time.
Here's my advice. Are you taking anything for nausea? I am unable to function on phenergan, at all, I took zofran for a good bit of my pregnancies. A word of caution with that - its notorious for causing horrid constipation and headaches. So be sure to add in a stool softener, a LOT of extra fluids, and walk as much as possible to keep things moving...
As far as your son, your husband quitting his job shouldn't be on your radar. This is temporary and WILL pass. Is there a daycare nearby? A Mother's Day out program? It's summer - find a high school or middle school kid to come into the home a few hours a day. Those options are all less costly than your husband quitting his job or your health.
Get your husband to use baby gates to create a "safe room" for you and your toddler. Before he leaves for work, maybe he could leave out a sippy cup of water, some drinks for you and some snacks for you both... I know there are days you just literally can barely move.
Hang in there and remember that this WILL pass. There are some websites out there, I think one was called HelpHer.
If you feel better after IV fluids, try to do that on the days your husband is off work, it may help
you get through the few days following. The dehydration makes you feel like death and seems to just kick off more nausea and vomiting.
Good luck and I hope you are feeling better sooner than later.