TBH, I think all manner of thoughts are normal in this situation. I have experienced a whole range of emotions returning to work this time round.
When I found out we couldn't afford for me to stay home (DD was about 5 months old) I spent several nights crying (grieving), stressed out because Phoebe was always fed to sleep, angry at the choices we'd made, angry that DH owns his business and didn't just have a 9-5er. I am still sad to leave my babies on work days, but I really like my new job and I look forward to going to work. Really, I think a range of emotions are normal.
We are doing ok with the work/family balance, although sometimes I feel DH values work over and above our family. This is something I'm struggling with atm, feeling that I am the only one who holds our kids as my first priority.