Returning to work after my first child was hard work but we quickly settled into a new routine. Now a couple of years later I'm back at work again after a second gorgeous boy. It's definitely challenging and the balance between family, career and me time is not always easy.
Remember there's always a compromise somewhere...At work, try to get comfortable with 'good enough' versus 'perfect'. Make sure you don't miss out on important family milestones. At home, try to outsource anything that you don't enjoy - e.g. cleaning. Try to work out what makes you feel refreshed/relaxed/inspired/energized and set aside a fixed time to do this on a regular basis. :-)
I think the best thing to do is to make a really good schedule. First, write all the different categories; for example, self, partner, kids, work, household. Then write in all the sub-categories for each of these. For example, self can be divided further into health/fitness, education, relaxation, spiritual development - whatever suits you best.
Now allocate whatever time you think is necessary for each category. Focus on the important ones first (hint, self is most important, followed by the other people in your life). Most important doesn't mean you need to assign the most time, though.
Now allot schedule space to each bracket of time. Try to set it up to work with the natural rhythms in the day. I assign the baby's nap time to jobs where I need to focus. Try it out for a while, and adjust the areas that don't work.
Now stick to it. You'll be much more productive and wont feel guilty for taking regularly scheduled me-time.