Congratulations, you are indeed in deep doo-doo.
You would indeed be on the hook for the 1st. So the question now is, what is the amount of the mortgage vs. the likely proceeds from the sale.
Don’t forget to include the condition of the unit when you take over months from now, the full selling costs probably months later, and the then-balance on the 1st, including all late fees, penalties, etc.
