This too shall pass.
It IS exhausting having a baby at ANY age. There are pros and cons to all ages of which you become a mum for the first time.
Ask your hv if there are baby groups near you with a younger membership?
Look into what it would take to go back to work (always worth doing regardless of the finances unless it's actually leaving you much worse off of you didn't. If you're basing it on childcare costing more than you alone would earn remember the childcare costs are half dads responsibility too).
Find other things to do where you might meet other parents.
Keep in mind, that it actually really won't be long at all until your child becomes less dependent on you and you can go out of a night, away for weekends etc and even when your child turns 18 you'll still only be 41/42 which is plenty young enough to do all kinds of things.
As wishingitwasfriday says, also don't fall for the false presentations people make on SM. It's entirely possible some of those seemingly "living it up" would love to be in your position.
I didn't have dd until I was nearly 30, but only those closest to exh and I knew that we'd been trying for a family for almost 7 years by that point. A combination of illness, mc/ectopic pregnancy, several surgeries, exh being deployed meant that we didn't become parents as soon as we planned. Meanwhile, those who didn't know us as well, as far as they were concerned we were just a young married couple enjoying ourselves, going away on holidays, long weekends, nights out etc if SM had been around then I wouldn't have been posting my heartache, worries that I'd never be a mum, I'd have been coping by making out all was fine.
I was absolutely exhausted when dd was this age, wondered at times if I'd done the right thing having her when I did (I was still one of the younger first time mum's in my social group) even though if I'd delayed chances are it would have been even more difficult. I had only one other close friend who was also a mother. At times it felt like I'd never escape the endless round of feeding/changing nappies/bathing/laundry etc
I've friends in my close friendship group who if you went on their SM you'd think were child free by choice, living it up having great careers, holidays, nights out etc - because we're close I know that actually they'd have loved to be parents but for various reasons it's not been possible for them (Ivf & other fertility treatments actually have relatively low success rates, adoption isn't for everyone and even those that want to adopt aren't always successful). You rarely know the full story unless you're really close to people.
Weirdly due to life circumstances I've ended up living somewhere where I'm now older than most of dds friends mum's so I'm seen totally differently here!
Things change/evolve. As your child gets older not only is there more they can do (which is great fun) but you can do more too.
If you're in Kent and he's working in/around London why isn't he coming home? Many London commuters live in Kent and go home most nights.
But don't worry it will always either be or feel like now. That's why I said "this too shall pass" all stages of life. Good and bad, don't last forever. So while it can be heartening to think you'll have more independence in the near future, don't forget to enjoy now! This baby won't be this age again.