Like others have said, you need to start by doing a budget so you know whether you're struggling because your outgoings exceed your income or because you're spending too much on non essentials as a household.
Go through the MSE budget with your partner to see where you stand. Also follow the advice on cutting costs, increasing income, and prioritising. This is a joint enterprise, so shouldn't all be on you. How is he with money?
Your eldest should be paying a decent amount of board and the three of you (and any other teens or older in the house) should all be cooking a meal or two a week. Can you all get together and agree a week's worth of meals that can be batch cooked and reheated - so curry, chilli, bolognese, slow cooked pulled pork etc. Also maybe have things in the freezer that can be cooked quickly (as well as frozen batch cooked food, frozen pizza, beige and chips etc) and also a supply of eggs, beans, soup and bread for easy and quick light meals. Then do a weekly shop or delivery for the ingredients.
On the debt, do not add any of it to the mortgage while your finances are in such a perilous position. Almost everyone who does this will run up more debt and ends up with a bigger mortgage and debt on top. If you haven't missed any payments, you might be able to transfer the balances to 0% interest deals so you can pay the debt down without a lot of the payments going on interest.
When you have done your budget, if you post it on the MSE debt free wannabe forum, you'll get advice on what the best course of action is to get out of debt.