Move fast on three fronts. First, freeze or cancel the cards immediately, ideally through your banking app, which works in seconds from anywhere; otherwise call the bank's emergency line, and note that Visa and Mastercard also run global assistance numbers that can block cards and arrange help. Second, if theft was involved, file a local police report promptly, since insurers and some banks require it and hotels can help with the language. Third, check your recent transactions and dispute anything fraudulent.
For surviving without the card: card networks and many banks offer emergency card replacement or emergency cash advances abroad, transfer services can send money for cash pickup within minutes if someone at home can help, and mobile wallets on your phone sometimes keep working even after a physical card is stolen and replaced with a new number.
Embassies don't hand out money, but they can help you contact people at home and, in genuine destitution, some governments offer repatriation loans as a last resort.