as a member of LLC after fired am I responsible for building payments

Being terminated as an employee does not terminate your rights or obligations as a member of the Llc.  Llc members are not normally personally responsible for the llc's obligations, but if you were responsible for the payments before you were terminated as an employee, your firing should not affect that, unless the instrument pursuant to which you were responsible for payments (llc members' agreement, guarantee or surety agreement, employment agreement, whatever) provides to the contrary.   For example, if you signed a guaranty which said you would be responsible for the llc's building payments only as long as you were employed by it, you would no longer be responsible.