Hey
I'm so sorry to hear you're feeling like that. It sounds to me like you're struggling with PND/generalised anxiety. This is what I have and my symptoms are the same as yours (constant worrying/negative thoughts, always feeling overwhelmed, just wanting to enjoy your life with your kids and not being able to).
If you haven't already, you should go to see your doctor. This is what I did.. He referred me for therapy, but he said I'd probably be on the waiting list for about 3-4 months so he recommended taking antidepressants. I said no at first 'cause I'm breastfeeding and was worried it would affect my baby, and because I feel generally a bit weird about antidepressants. I ended up going back the next week though 'cause it became clear to me that I wouldn't be able to cope without them.
The antidepressants are a GODSEND. I really don't know what I'd do without them now. In fact I once had to go without them for 2 days 'cause I forgot to pick up my prescription before the weekend and it wasn't pretty. They took about a week to come into effect, and I did feel just a bit spacey/sickly in the evenings for an hour or so while they were kicking in, but it's not bad at all, and totally worth it. I've just finished my course of 6 sessions of CBT (cognitive behavioural therapy - where they basically teach you to recognise your thoughts and feelings and challenge your behaviour and thus overcome your anxiety/depression) and I've found it really useful. During the course of these 6 sessions though I came to the realisation that I have a few unresolved issues from my childhood that I think are affecting me and perhaps causing my anxiety/low mood. My parents split up when I was 5 and my mum had a hard time dealing with it.. she ended up in a relationship about 2 weeks after my dad left and the guy was literally sitting in our living room playing his computer in my dad's dressing gown. You get the picture.. I'm not saying I had a deeply traumatic upbringing or anything, but this, along with a few other things, definitely had an impact on me and the way I am today, I've realised. My mum was always really stressed as well when I was a kid, which I think has turned ME into a complete stresshead. So now I go and have a kid, and I get PND, and I'm thinking the reason is that I'm terrified of her going through the same thing I went/am going through!
Anyway...I'm sorry but I have to cut this short 'cause my DD has decided she doesn't want to sleep without me now so I have to go to bed! My OH is bouncing her until I'm ready to go to bed

So I'll continue tomorrow...
Hope you're feeling better soon...just know, it's perfectly normal, and there IS a way out