I remember having that much energy and look forward to doing so again someday!
Actually, having said that things aren't too bad. I've been sleeping really rather well (all things considered) over the past 3-4 weeks and have recently recovered my ability to multitask! It was a great shock (and a great slower down of your working day!) when I discovered that I was down to one thing at a time. So I'm still happy with my theory that "baby brain" is really all about sleep deprivation.