The feeling of friends leaving the city :(

A nice group of friends slowly started to get shorten, people leaving for US, Europe, getting married, moving to other cities! Such a bad feeling, the city feels emptier and emptier, you don’t feel like going to the usual places as they hold little meaning without friends..how do you deal with this? And as someone who doesnt make friends easily how do you make new friends? Basically how do you fill the void left behind? Edit: To those who have been in similar situations, what helped you eventually? Was it making new friends? Or replacing that time with some other activity?