@Lulu2021 sorry some people are being so nasty.
I have a few thoughts, for what they are worth.
First, I wondered whether you have considered returning part time once you return to work? I only ask because I have a demanding role (similar salary to you), only one kid and a supportive partner, but my mental health has really, really, really suffered over the past five years as I have attempted to balance both child rearing and working full time in a stressful role. I am going part time from January onwards and frankly wish I had done it earlier. Is this something you would entertain, even for the short term? It would solve a few issues.
Second, I wonder about a meeting with a financial advisor or something similar, to look at debt consolidation.
Third, as your car is on finance, this will be cutting into your take home a fair bit. Could you return it and buy a cheaper run around, and consider leasing when you are more sorted? You mightn't be able to do this, admittedly, if you don't have anything spare to buy a cheap car. But this cost would be one of the first I would look at.
Fourth, I would write down all outgoings, and see what you can cancel, and what you can reduce. You may find you save £50-75/month which will feel like a lot when you are balancing a tighter budget.
Fifth, you said you pay £200 for your student loan ever month, and 9.1% pension. You could see if you could pause either or both of these payments for the short term, unless your youngest is five. Not ideal, but...