What do I do when my TA workload is more than expected?
You should consult with your department, asking explicitly:


  How do you want to proceed, I feel like these conditions are excessive and were not part of the deal as far as I know.


Come to the meeting with your signed contract / TA paperwork.

I assume, your department cares about quality of the education they provide. Don't let them pin this on you, you are a student first of all. If they employ you, they are responsible for your performance as a teacher.

Other answers didn't pause here:


  I feel extremely overwhelmed by this workload and my depression has made this worse I've cancelled class at least 5 times this semester because I couldn't get out of bed


I suggest you immediately seek professional help. Your university must have services available for students (and be paid-for by university's health insurance), especially given recent attention to mental health crisis in academia. That is your responsibility to take care of yourself. You are also a real person, not just a robot TA, don't let mental health issues fester.