Hello and welcome to the forum.
In your situation, there is a possibility that the data on the memory card has become corrupted and because of this, the camera itself isn't recognising it when inserted. As you are away from home, I would suggest taking the card into a photography store and asking if the contents can be safely removed and backed up onto a CD or DVD. Then, once you are 100% sure that your existing photos are safely backed up (I usually check and double check numerous times), try formatting the memory card in the camera as this should leave you with a fresh, uncorrupted card.
Usually, these specialised photography stores have more sophisticated memory card readers than the camera itself so even if your camera cannot read the card, there is a chance that the store will be able to safely retrieve the data.
Hope this works for you,
Simon
