Single mum here, with a two year old beagle. I absolutely feel your pain but it really does get easier. I had done all the reading, grew up with dogs and my Uncle is a champion dog trainer who has in my lifetime has never been at a family event for more than four hours. The people saying how this post makes them sad, ignore them. It's hard and no one shares the tough bits on instagram.
My daughters were 8 and 9 when we got the dog. I collected him at 12 weeks so that the children were back to school, (he therefore came potty trained and pretty much slept through the night from night 3). I did everything right then turned over on my ankle and couldn't walk for three weeks. It was a nightmare. I drove my automatic to the park before and after school and sat on a bench so my daughters could run around with him.
It is really hard work and a huge adjustment and if anything, more than a baby because at least you can put a nappy on them and get out the door. I'd take having my two children as toddlers over another puppy right now!
This is what I did, I don't know if it's right but it worked for us.
I worked from the kitchen for about 6 months and only when he was a bit older did I let him into the living room. He was 18 months old before I gave him more access to the house. This meant that he had company and I only had one space that we kept completely clear (children always leave a trail of destruction) and that reduced the problem chewing. I was also sat right next to the back door which helped with reinforcing the potty training.
I did play a lot of tug games and do training for five minutes at a time but crated him regularly for naps (I began to notice when he was behaving like an overwrought toddler and needed to sleep). In a few weeks, he would go to bed when my children did (7:30ish) and wake up at 6:30-7 the following morning. He still will take himself off to the crate at 8pm and wakes up around the same time.
I got a dogwalker for one day a week. We all got the flu when he was three months old and none of us were well enough to leave the house for three days so I realised that I needed a deeper bench. Around here, they are so popular that unless you see them regularly, they won't book you in for a walk. When he was young, just that hour when I wasn't responsible for anything or anyone in the house was bliss! Plus when things come up, I always have someone who will help.
Find a dog park and make dog friends. These people understand your pain and are happy to help wear out your dog and give advice and moral support. I find that that if you ask questions seek advice, people are really happy to help.
I think that even without the dog you would be overwhelmed right now but it will be ok, it is flipping hard and definitely worth it. I don't properly remember my first year with him but he is currently napping on the sofa as I type and I won't be without him!