I just lost my largest customer to China.

That doesn’t sound strange to me.
Your end customer was evaluating Chinese crap.
Your distributor caught wind of it and drove down their inventory.
End customer decided Chinese crap is crap.
Distributor is caught with no stock and pants down, places hurry up order.

Everyone bitches about the squeeze to drive down their costs, doesn’t mean everyone is going under.

People are flaky, and it makes it hard to do business.