Two weeks ago, I received this succulent as a gift. Inititially it looked very healthy with green leaves and bright pink tips. I left for a trip and upon returning; the bottom leaves were lose and falling off and the colour had changed from pink to white (I had left the blinds down and it didn't receive much light). Thinking it needed direct sulight, I placed it in front of a very bright, sunny window. This seems to have made the situation worse as the leaves are still falling off. I think it may be a graptopetalum but I cannot find something that looks identical to it online. Hopefully once I've identified its species, I can figure out how to save it! Any advice would be much appreciated, thank you.