If you qualify under the statute as head of household and meet the guidelines, the judge will have no choice but to dissolve the writ of garnishment. Many people in your shoes can't afford an attorney- as long as you can testify and have some proof that what you say is true and it meets the statutory requirements, you should be fine.
It's a hearing. You will be sworn in and then testify to facts that you really are the head of household. You need to look at the statute and definition of Head of Household under FL law. Then you need to testify and present evidence such that you qualify for head of household. Helpful documents would be your W-4, last years tax return, etc. The sole purpose of the hearing is to determine if you qualify for the head of household exemption. So, don't talk about anything else (the reason you can't pay the debt, that the creditor is evil, etc, is not relevant and wastes time).
If you file bankruptcy, yes, this will go away. After all, bankruptcy is the RIGHT tool for when someone cannot pay debts.
My colleagues have answered your question on the head of household exemption. To answer your second question, yes a bankruptcy can discharge most of your debts. To see whether its a viable option for you, you should consult with a few bankruptcy attorneys in your area. Find the attorney you feel comfortable with, if you do decide to move forward. Good luck!
The asking of and answering general questions does not establish an attorney-client relationship. Please consult with an actual attorney in your local area before deciding on a course of action.