If you are able to complete the assignment, you should give it your best shot. But if you are too sick to complete the assignment:
Speak to your Prof or TA
Explain the situation to them and ask if they will give you extra time to complete your assignment. They may request that you use the absence declaration in ACORN to record your absence from class.
Speak to your department
You can request special consideration to submit your assignment after the semester ends from your department.
File a petition
If your assignment deadline is close to the end of the semester, you may have to contact the Faculty Registrar to file a petition for an exception.
See a doctor
Seek medical advice before you move ahead with asking for accommodations.