Thank you for your question. Unfortunately, there's no way to reduce your mortgage unless you contact the bank and ask for some forgiveness. They will not be inclined to do this unless you are broke, and they do not have equity in the house. You would have to stop making payments and this would destroy your credit the same amount as if you foreclosed. You could always just walk away and let them foreclose, but I don't advise that.
I'm truly sorry. Also -- Zillow isn't always right. The only way to know what your house is worth is to do an appraisal by a qualified real estate appraiser.
Please let me know if you need anything additional. If not, please rate positive.