1. leaving the house to exercise in some form, usually walking, every day. If you have a runner or live near high-traffic streets or other hazards, get one of those children's backpacks with a leash handle, I am convinced that product has saved countless lives. If you walk enough, sleep will be easier for everyone. You don't have to exhaust yourself or do too much, 20 minutes of walking may be enough to help.
2. Finding something the kid would focus on for a long time, while I would listen to or watch something adult oriented. Having to mentally live in little-kid land too long is really alienating. It is hard to say what will contain your kid, but there is something out there, some of it seems a little cruel to me like freezing their toys in ice and then telling them to get the toys out, but kids love that kind of thing for some reason. I preferred stuff that didn't require any assembly or preparation, but that does tend to cost more money. I had multiple train sets going (duplo and IKEA) for a long time, and I didn't really clean them up because it was more engrossing as a huge ongoing project than something to pack up every day. I also think that if you become the sole source of entertainment for your child they miss out on the ability to entertain themselves. If you are only having one child this really becomes a big deal, because you're going to be their sole source for a lot of things in life and you have to choose what things you're reasonably able to provide. Love and caring need to be prioritized over entertainment. Let them get bored.
3. taking the easy way out when it made sense to do so. Before I found good engrossing toys, I had to move homes. SO I had my kid watch television while I worked on packing and cleaning for several weeks to make it happen. It was fine. Nothing bad happened. A lot of my exhaustion at that time was putting a lot of pressure on myself to do everything correctly, it may be worth breaking some of your own rules at least a little to see that things will be okay. After watching a ton of TV during the move, I was more comfortable watching a sane amount of television when it made sense to do so. The moms I know who are the most exhausted with toddlers are the zero sugar/no screen types who don't ever give themselves a break. Do what makes sense for your particular situation and don't worry about what other people might say, it literally does not matter. Maybe you need to eat off paper plates for a year for your own sanity, who gives a shit? its fine.
4. Having another kid helped more than anything. I was so locked-in on my focus on the first one that it was difficult to do other things for myself. The moment I had two to worry about, it broke the spell and I had to let go of a lot of things that I was dead-set on before that. It just wasn't reasonable anymore and I relaxed a lot. I have seen that kind of focus in a lot of women who only have one kid, especially those with sons. Ideally your kids play with each other and like each other. I wish that were a guarantee, but for the most part it works out when they are small, and that is when it matters the most.
finding some friends with kids can really help. its not easy, but it can be free. libraries have story times for small kids and it is a natural place to meet other parents. church also tends to be a good place though I don't know if that is something you're interested in. If you have extra money and don't mind spending it you can do daycare type programs for half a day here and there, if you do not have anyone to help you out (like you live far from family or whatever) then it makes sense to do that. If you have family nearby you have to get them to help you on a regular basis. I had zero help and it made things much more difficult.