In Over one's Head

Example 1:
I want to graduate early, so I registered for 2 extra classes this semester. I thought I could handle it, but I'm starting to think I am in over my head. With all the homework, reading assignments, and classes to attend, I'm not sleeping well and I'm feeling overwhelmed. The deadline to drop classes is next week. I'll probably have to drop one to make things more manageable.

Example 2:
My new job just started. It was probably a terrible idea to lie on my resume about my experience. Now my responsibilities includes skills that I don't actually have. I'm totally in over my head. I will have to be honest with my boss and let them know that I'm not actually qualified for this position. 

Explanation:

To be in over one's head is to be overwhelmed by something you can't handle. Usually a person puts themselves into this situation.
In Example 1, this student has registered for too many classes. The workload has become a problem. It is more than the student can handle.
In Example 2, this person gave false information to her employer, now they have responsibilities that are beyond their knowledge and experience. They cannot handle their job. 

Use the be  verb with a possessive pronoun to form sentences.
I am in over my head
She/He is in over her/his head
We are in over our heads
They are in over their heads 

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