The life of a working mother

I've had this "job" called motherhood for over 4 years now and while it is very enjoyable and extremely rewarding, it also gets harder and harder every day that passes...
I love my children with all my heart, they are the biggest blessing that God has given my husband and I, but my life as a working mother is so unfair sometimes...
I'm on the verge of crying every morning when I drop them off at school and then at the highest of joys when I pick them up in the afternoon...
I think of them every hour I'm at work and suffer every time I have to interrupt their precious sleep so that we can all make it on time every morning... I don't like "abandoning" my kids, I don't like feeling like I can't give them their place as #1 in my life, because there's always something: a meeting, an appointment, an errand to run...why is it so hard sometimes?
It is somewhat comforting to know that this life is not exclusively mine and that's why I like to think that other working mothers go through the same feelings as me...
Some nights I'm so exhausted that I don't even have the energy for nightly prayers or story time and I find myself taking shortcuts with my kids... why?  am I the only one?  I pray to God that He gives me the energy and enthusiasm I need to carry on with the life of a working mother... this is definitely tough!