At various times in the past 18 months I could have written everything you have. These might not be in a very good order but they are the things that have helped me.
Surround yourself with people that support you - there are a hell of a lot of people out there who won't - for me it is certain family and friends, but very specific ones.
Try and enjoy the time you do have. Weekends - you will be knackered, I am not underestimating this - but think what are your strengths? For me it was my dd's (3) unlimited desire to make things, and I love creative if messy times too, and we'd do that every day off we had together. DD loves museums - I think just to tear around somewhere different - and in that environment it is easy to give my undivided attention - we go at least monthly and she asks about it and loves it (a lot are free, too, which helps).
Use time most people would not consider "quality time" - for us this was buses in the morning and evening, we chat, cuddle, she eats, we catch up.
Think where you want to go. I want my hours down to 40 and my commute door to door including nursery drop off and jumping in puddles and... well, you know, - less than an hour. I think I achieved this last week though am in a cold rented house with money worries - but my hours are down - well, they aren't but I get to take the time owing which is the same thing to me given my past experience which was 50+ hours and the commute is loads better. I still don't have the home, the money, the location, but I feel like I know where I am going and it is just taking much much longer than it might take some but I will get there.
You need to really really think about the usual parenting issues - picking your battles, etc, because they carry on for a long time.
Look after yourself, if you ever find the time. I rarely do, but I do know it makes a difference. I really feel for you.