If we are required by God's law to suspend our contribution for a time because of some necessity we are not forbidden to receive the sacraments.
Is it really necessary to suspend contributions at this time? The priest is good enough to give you the Sacraments, but not good enough to support materially. He needs to eat and pay the bills, doesn't he? I would stop supporting materially if I were out of that chapel completely.
I'll give you a few pointers to help alleviate your concerns:
Request a Mass (or many) be said by your priest. The stipend goes straight in his pocket. This money will feed him regardless of how stable his priory's finances are. This is a very straightforward and time-honored means of supporting your priest.
If you attend a mission chapel, drop your contribution in the Priory collection. That money goes straight to the Priory for the purpose of housing your priest.
Talk to your local treasurer about how much cushion your chapel has for paying the bills. If you're really month-to-month, that person will know. I'd imagine most chapels have plenty of cushion for keeping the bills paid even if incoming collections dropped to zero. Perhaps ask him/her to let you know if the chapel becomes in need of money for basic operations.
If you're really ambitious, talk to that person about any debt your chapel has and who is it owed to. I wouldn't presume that your chapel has to keep up with debt service just because you have a newish or newly-renovated church. The Society makes loans to itself and it's possible that the construction money was simply borrowed from elsewhere in the Society.
Or, if you're
really wild and crazy, pay a bill or two directly. It's a known in a hierachical organization that a % of money given goes up the line. Buy the week's flowers, restock the cleaning supplies or bathroom soap, or drop by the local utility and see if they'll let you make a payment on your chapel's account. It might not be the most efficient, but you'd know what your contribution is and isn't supporting.