First of all, congratulations on all of it! It sounds like you have a great life, albeit, a busy one. Just dont be so hard on yourself, this is a crazy time. 2 small kids, full time work, etc etc, takes its toll. You will get back to a routine. In the meantime, here is what I recommend (from personal experience, might I add!)
Maybe you are going to bed TOO early. In an effort to get plenty of rest, your body might be rested by the time you wake up at 3am.
I always try to meditate if I cannot sleep. Meditation can be daunting, so simply concentrating on relaxing each part of your body and emptying your mind counts too. Whenever a nasty worrysome thought comes, literally tell it to go away.
If you absolutely cannot sleep, get up. Read, drink some warm milk, take a bath. Do something other than lie there. I also find that mindless tv helps too. I get sleepy.
If nothing else works, a trick I also use is to daydream. Plan your perfect day. Only positive things. Think about what you would do from the moment you get up, to the moment you go to sleep. Not chores or what you HAVE to do, but what you would do if you could do exactly what you wanted. Win the lottery! Go shopping! Buy a new house! Take your kids somewhere. I find that "dream" puts me in a happy state of mind, I relax and fall asleep before lunchtime in the dream!
Best of luck!