I would make savings now, and start looking for a part time job and viewing childminders/ nurseries.
Switching utilities is easy - money saving expert has good advice about the best deals.
Go back to your GP about your acne. There are various lotions and tablets they can prescribe, even if the first ones didn't help. £30 a month is too much on skincare when you are in debt, sorry.
Cut back on haircuts, I don't know anyone who actually has a haircut every 8 weeks!
I'd also start looking for a part time job, see what comes up. If you haven't worked in 20 years it may take a while, so I'd start looking early. Many people return to work at 12months, it may take you that long to find a job. Also visit some local nurseries and childminders to see what is available.
If you will be earning minimum wage it makes more sense to work at the weekend or evening when you won't need childcare.
One option initially would be something informal like cleaning and ironing in people's homes- you could do a few hours one weekend morning - £10 an hour where I live and cleaners are in great demand.
I think your dh is probably worried that you won't return to work even when baby is older, if ever, and he will end up responsible for paying all this debt back. Taking on a few hours a week in the next few months will treasure him that you are building towards bringing in more money. Your youngest will qualify for some free childcare at some point and if you are in work already it will be easier to build up then.
Also are you getting therapy and medication for your anxiety? It sounds like your anxiety contributed towards the fear that led to spending £4k on private medical care, and it would be good to address your anxiety before it leads to any similar episodes in future.