Cindy, everyone has their own experience, and many of the negative posts seem to originate from the environments with bad coworkers and poor management. Remember that most people are apt to voice their displeasure and the many with positive experiences have not chimed in here.
Clearly, not all work environments are reflected in these posts. Ask yourself this: if it's so awful, why do people stay in it? I'm sure they're quite capable of doing something else for a living.
It's true that this is a very physical job and you will be tired at the end of the day, but working with animals can be very rewarding for those who love caring for them. Explore the various animal-care industry job options (hospitals, clinics, private practices, nonprofits, universities, research, etc.), and decide for yourself.
No matter what, no one can take away your knowledge, so remember that your education an investment in yourself--a college degree is never a waste of time.