Don't Bite Off More Than You Can Chew
(don't assume more responsibility than you can handle; don't be overconfident)
Hold on there, Sam. Where are you running off to?
Oh, hi Lloyd. Can't stop to chat. I'm already late for work.
It seems like you're always busy lately. If it's not work, it's studies or something else. You don't have time for your friends anyway. When you took that full-time job I warned you: Don't bite off more than you can chew!
I think you were right. Now I see that it was a mistake to take on too much responsibility all at once. My grades in school are already starting to go down.
There you are! Why don't you cut down on your hours at work and maybe drop a course or two, at least for this semester?
Maybe I'll do that. At this rate my health is liable to suffer, too.
take on = assume = 引き受ける
be liable to 〜 = 〜するおそれがある