I heard that his girlfriend died and dat wud explain how he would send a postcard 2 sum1 but he can't cuz she's not alive anymore. And nostalgia means sorta missing sumone or a time; like, he misses the time his girlfriend was alive and they wer happy and in love.
Sorry if sum1 typed this I don't mean 2 copy even accidently just want to refresh the thought if it was already typed so sorry.