It's like imagining being the last one in a zombie apocalypse but the sadness and horror and everything negative times 100000. Actually, more. Because Sherlock cannot service without John and when he sees that John faked it, he will mentally kill himself for not seeing that John faked his death. Yup.
A picture a boy called George, forced into a frilly dress and with the most truculent expression on his face. The basket he's holding contains bay leaves, which in the Victorian language of flowers means "I change but in death". His twin sister died and his parents wanted a keepsake of her so this was the nearest they could get...I'm not sure what parent would today dress their son up as his deceased twin sister - I imagine, although it seems strange today, but maybe they found comfort in it