Contact the SIM card's service provider and check if the lost card is turned off and no unexpected usage occurs, If your phone is stolen, report the incident and request your service provider to immediately block the SIM card.
Sorry to hear you lost your SIM card while on holiday, that is unfortunate. I would love to help by ordering a replacement SIM for you. I shall send you a private message now to obtain the details required. Please look out for the purple envelope in the top right corner and get back to me when you can.