My battle bet is fed, healed, and happy, however it reads "Oh no! None of your pets are eligible for battle. You might want to make sure that they're well fed and happy!" What is up with that?

Check your statistics to see if you are already in a battle.

oi! yes i forgot to click at the end of a battle! thank you that was very frustrating

No worries. I appreciate the token btw. Not necessary but I appreciate it. :)