Do a benefits check, does your dh get carer's allowance?
Call all companies, bank, utilities, credit card, loans and tell them your income has halved. Some companies are better than others but they all have policies to help.
As you have a disabled child in the house bailiffs cannot legally enter and remove items, your dh may also be classed as 'vulnerable', I'm not suggesting you stop paying utilities just that if the companies do hot cooperate with you they are not going to get anything by taking you to court.
Check if your new income entitles you to 'warm homes discount' and if you are apply for it this is £140 towards your winter fuel bills, sometimes given as cash.
Check your council tax, I recently put in a claim for UC and my council tax bill dropped a huge amount. Also overpay your council tax if you can so that is is paid off quicker and then put the same amount in an 'emergency' account.
Have a serious look at your food - do you throw food away? If so this is where you make your cuts, so rather than buy fresh veg that is thrown out when not used buy frozen or tinned.
If your dh doesn't cook now is his time to start. Lots of things our parents or grandparents ate took time but were much cheaper eg pancakes and Yorkshire pudding batter (same batter) cost pennies but can be the base of a good meal. My mum would do a sort of toad in the hole but with lamb chops.
Stop going to the shop and get deliveries, Iceland do free deliveries for spends of £40, if you are not in the shop you won't be tempted with, "that looks nice" if you are paid monthly then get a shop once a month and set aside a small amount for extras you might need. Milk, bread and cheese all freeze really well so if you have enough space buy monthly.
Also join a cash back site and do all your shopping online.
Meal plan.
Look at your bank account and other accounts, you might get a bonus for opening a new account or transferring to a different bank.
Do your 'top up' shop locally, my local butcher often puts an extra sausage in a bag if it is the last one, or knocks a few pence of the price and gives away for free 2kg bags of the ends of cooked meats - great for the cats.
Fanally
Take a few deep breaths and remember there will always be someone on MN to lend you an ear.