You say you won't be able to change working from home.
Yes, you probably can.
I felt that. I worked from home for years and by the end of it I was crawling up the walls.
But I felt trapped in the job - it was so convenient, I never had to worry about childminders or sickness, I felt really scared of applying for jobs which were not home-based, but at the same time, I was so lonely that I knew I had to take the risk.
Please consider taking a job that is either office based or hybrid, so you at least get some time out of your home where you have to dress up, go to an office and immerse yourself in something different from home and kids. I know it's scary and the financial support is probably still crap, but it's really worth it for the sake or your health and happiness. If you have reasonable transferable skills, you have a decent chance of finding a job that is flexible enough to enable you to work and still be there to deal with emergencies and not be so overwhelmed by working and parenting that you have a nervous breakdown.
For the first few years of parenting alone, I needed safety, cocooning and time to introspect. But looking back, I hung on too long to the safety and I was very much in danger of going the path that you are on, feeling really unhappy and lonely. You have to break out of this and one of the most constructive and accessible ways you can do it, is by reassessing your work set up.