I'd agree that you depressed, but not the rest of what you're saying.
- You're a devoted parent = epic achievement
- You deal with chronic illness, an enormous challenge to even the most positive and well-supported person
- You are 35. Very far from old. You still have a good 30 yrs in which to learn a trade/profession/start a career.
At the moment it may feel overwhelming bc you're comparing yourself with others who've already invested years in study and careers, but if you focus on your own life journey, the possibilities are endless.
I'm not in UK but where I am there is an online tool for career assistance. You answer a series of rapid fire questions and it spits out a list of career paths that match your interests. Then you click on each answer and it tells you the training involved, the employability rate, the salary expectations etc. you can keep clicking through for more specific advice.
There's bound to be a similar tool in the UK.
The next step is to plot a route to starting the training/study. It may involve a return to FT study, or PT and pt-work - that's entirely up to you.
But my best advice is to limit your research and planning to 1-2hrs a day. This allows you to commit to change without getting overwhelmed. When your hour is done, switch off your laptop and get on with the rest of your day.
As you edge towards your goal, you can incorporate steps like cv writing and cover letter writing. There is a lot of good, free advice on the net for this.
Little steps! Think of it as a suitcase that you have to thoughtfully pack, one item at a time.
C'mon, you can do this. Everyone can contribute positively when the right framework is in place.
Let people help you too; this may mean seeing your GP for help with depression, therapy for working through difficult to manage feelings, careers advice, asking trusted friends fir support.
I'd help you if you were my friend!