Bite off more than you can chew.
Bite off more than you can chew.
The phrase "Bite off more than you can chew" is a vivid way to describe taking on more responsibilities or tasks than one can manage. It's commonly used for situations where overambition leads to overwhelming scenarios, serving as a caution to take on only as much as one can handle.
I think I bit off more than I can chew with this project.
I've taken on more work than I can handle with this project.
He's overwhelmed because he bit off more than he can chew.
He's overwhelmed because he has taken on more than he can manage.
Taking on both a full-time job and a part-time course was biting off more than I could chew.
Balancing a full-time job and a part-time course is more than I can handle.