Thank you OP, that's very kind of you. You'd be surprised how easy it is to start thinking like I do, and focusing on how the lives of others are even harder than your own, as I say, it really helps put things in perspective.
I'm glad you enjoy a walk, and hope that you'll also work on doing more of it during the winter months, if it helps, set yourself up with a treat to have when you get back, a cup of hot chocolate, or a nice bubble bath, some sort of reward to give you even more of a high for making the effort to go out.
With regard to the anti-depressants, I've been on them for years due to a chemical imbalance, rather than a life event, so have a lot of experience. Can I ask when you last had a review of your meds, as you may be thinking what's the point of taking them, if they're not making a difference, whereas it could just be that your body has got used to them and you need a different type, or that you're not currently on a strong enough dose, so if you haven't spoken to your GP recently, please go and have a chat about it. At the end of the day, it's hard being a single parent normally, especially with the cost of living as it is, but it's even harder if you're not starting off from a good place, and as you're clearly struggling, it does seem to me that you need something stronger to level up your mood, and help you to cope.
If you want to start practicing being grateful for what you've got, next time you go for a walk, think of me, stuck in bed, unable to get out and enjoy a good old stomp around the park, and then count your blessings because YOU can!!
Honestly, I won't begrudge you enjoying that moment!😁