Do you have an actual written down budget?
I raised dd alone and I've been where you are and worse! It's really hard.
I've always done a budget spreadsheet to keep an eye on things and so I know where I stand which helps my anxiety about such things
You seem to be doing pretty much all you can so I'm conscious I may well be teaching you to suck eggs!
You've minimised all your outgoings as much as you can
Do you regularly and consistently look out for and use discounts and voucher codes?
There are threads/forums on mse site that are usually good for this and the site generally is
Loyalty cards - I get loyalty cards for every shop I ever use. Some the loyalty points can be used in other ways so that you get better "value" eg I shop with Tesco and use my Clubcard points to offset my Tesco mobile bill which equates to double value of the points used
Heating - if you can manage the initial outlay I would recommend halogen heaters and electric blankets. Will at least mean you can reduce your use of the central heating or lower the thermostat at least. They're very cheap to run and the heaters have a lovely cosy glow too. I first got some when I was in a flat with horrifically crap storage heating that was extortionately expensive! Made a huge difference for me
Have you got the timer for the Central heating at optimum use? Eg even when I have mine on I have it that it goes off half hour or so before I settle in bed
Have you got your home as well insulated as possible? Not just the "big" stuff like the loft but also the "little" things like heavy curtains, well sealed windows and doors. Draft excluders etc
Wear layers - I can feel the cold and I've been known to wear leggings, t shirt AND pyjamas to bed!
Mse also has tips on how to adjust your car and driving style to keep petrol costs to a minimum. When I used to drive i read and applied it and i was shocked the difference it made!
Solicitors generally aren't experts in debt. I would urge you to speak to a specialist debt charity (don't pay for advice) as I think at the very least they may be able to get the interest frozen but a longer term payment arrangement
For income perhaps look at people per hour?
Something I'm considering doing myself
@rrhuth totally agree I came up with "creative" ideas for dd when broke that are actually part of some of her happiest memories!
The "80's" themed birthday party where I basically just had her friends over, they dressed in 80's clothes and we had "80's" food and drink and I played 80's cheesy music on a cd I created from my stash which I included ones that had a dance to go with it (mainly black lace it must be said) and I taught them the dances we had a great laugh
The Xmas I got her plastic drawers from wilko and filled them with cheap printer paper, new colouring pens and pencils, glue sticks etc which I picked up at wilko or pound shops or B&m but I also included eg a roll of kitchen foil just for her to use (she'd use it for "stars" in collages, I'll admit I had an ulterior motive in that it stopped me from running out of foil for cooking and not knowing!)
Many many carpet picnics and "breakfast for dinner"
Kids remember the love!
When dd was young - your ds age and younger - I used to head to bed once she was in bed as warmer under the duvet! Watch some dvds (pre streaming days and no Aerial upstairs) or read or do things like puzzles and cross stitch with the radio on
Who have you checked the benefit stuff with? Ime the best people for this are in your councils welfare rights office (sometimes they have a different name) as they are very well informed and even know of local grants/help that's available