@Turnthecandleson
I'm very sorry you're feeling like this. As many others have said you're not a failure! You have your own (mortgaged) home.
you haven't yet 'used your degree', but you still have plenty of time!
your DS is actually a very lucky boy! He has a mum (parents?) that love him & look after him, he's loved, fed & although this should be a given -isn't) isn't abused.
Attic bedrooms are brilliant. Kids play on the floor, or in their beds. They don't stand around like grazing animals 😁
DS has his own room, in a safe home. It's a LOT more than far too many kids!
Hes 4, if he doesn't 'have enough space to play' he has too much stuff! Declutter. He'll enjoy what he has more if he can access what he has & it's easy to tidy.
As for one room downstairs. I get the envy of bigger houses with 'live in' kitchens & separate utility etc etc. my current home is tiny, it would fit in the utility/boot room/kitchen of one of my previous homes. It was a big house, with a lovely garden, in a fabulous area etc and yes, it ws brilliant for entertaining
but, 'life'...
i love my little flat, it doesn't even have a yard & it doesn't have a beautiful view. But it's MINE & as long as I prioritise the mortgage, no one can take it off of me & I am incredibly thankful of that security. The rental market is a scary place, especially right now.
planters and a small shed, many of us would have given anything for that during covid lock downs & even now.. There's space to sit outside with a coffee/ice lolly and for DS to play with a few toys or have a small paddling pool. It sounds like you live in a lovely place where you can go for a walk & Play.
DS must be at school or going in Sept so childcare costs will be a lot lower. It has its difficulties too, but that's just life.
Take some time now to think about what you want to do career wise & map out a long term plan to achieve it You have a degree, so you have the ability to work towards a good job.
Get help (more help) with your anxiety etc & you'll see you're no failure! You have your life ahead of you with your DS, it's FAR from pointless - you just need to be able to see it for yourself!!