Schooling what to do??

I've been wanting to go back to school for years now. I had my last child last year in may and with my son turning 4 in Oct, starting school soon and me needing a better job I've decided it was time to go back to school I have done my research and I'm still stuck. I have a medical back ground so I know I want it to be in the medical field; I wanted to work in the ER but I'm an empathist and I know I couldn't do it. I have been going back and forth with what I wanted to do and I have figured it out but I'm stuck between 2 of them...

Labor and delivery or Ultrasound tech

Which do you think is best? I don't care about pay that is a bonus but I want a job that I can wake up to and not dread going to.