Hi OP,
I'm not sure why you're taking such a bashing. Personally, I am (almost perpetually) single and bought my flat at 26, outside the UK and away from practical family support. Frankly, at times it is overwhelming to be solely responsible for everything. Well done for getting yourself on the property ladder and for handling everything so well so far.
I got taken by surprise a number of times by the responsibilities and costs of home ownership, and while I'd not swap my independence and eventual stability for anything, there were times where it was just bloody exhausting. My single friends and I say that something has to give, no full-time employed adult can have all of the following at the same time: a full fridge, a clean flat, an empty laundry basket. Plus you're studying, which takes extra time and focus.
Ignore PP saying "I had kids at your age", your feelings are valid, and well done for recognising them and trying to to take steps to avoid some sort of collapse/crisis/whatever burnout looks like for you.
You don't say what you work in and if going part time would have any consequences on your current position of chances of progression. However, I am inclined to side with some of the wiser PP: yours 20s and 30s are the time to really establish yourself professionally, and 35k is quite the nest egg to rebuild.
Unless you are truly wiped out by the job and simultaneous study, I think the suggestions of augmenting your budget for support are a good idea. You should figure out what is causing you the most stress or seems the most unnecessary use of your time, and use some of the money to shove it off your plate (cleaning, food delivery services or meal prep, washing/ironing, house maintenance).
As someone who hates food shopping and meal prep, I regularly use services like Hello Fresh. Recently, on a task rabbit type site, I have been surprised to discover how many people are willing to prepare home cooked food for a reasonable price.
Lastly, think about scheduling some proper downtime. When overwhelmed, we forget to rest and it just feeds the cycle. Try to set aside some real recovery time for yourself (digital detox day, solo sport, a spa treatment, take yourself for a long lunch).
It is ok to struggle, you probably have a better handle on things than you realise, and you will find solutions. Good luck!