Thank you both for the extremely thoughtful responses.
My current situation is this: I'm a burnt-out English teacher in my 6th year of teaching. I originally took on teaching because I thought it would be a career that supplemented my interest in writing. Little did I know how consuming this profession would be, however. I have zero time for hobbies, nor basic life essentials such as family, pets, and exercise--frequently working evenings, weekends, and into late night just to stay par. Teaching really is a lifestyle--not a career--and I hate to say I've become bitter and disillusioned due to this fact. I know when to say when, and it's time.
In searching for an alternative career, I've begun to think about all of the things that have brought me joy and fascination in life: Animals have always played a huge role. I'm looking to challenge myself in ways I haven't been challenged before (science instead of the arts). And while I don't foresee a problem with devoting a good number of hours to something I'm passionate about, I am a little concerned about maintaining some kind of balance between work and life because of the problems experienced while teaching.
Am I looking in the wrong profession, or can one realistically manage such a demanding professional job, family, and hobbies as a vet?
Please, keep the responses rolling. I'd love to hear from others, as well.