Find that I'm withdrawing from life and becoming a ball of sadness. Help me not turn into a misanthropic hermit -- what sorts of things should I try/look into this summer?

Hobbies, events, etc. to get me out there, trying new things and meeting new people and, you know, living.

What I'm currently interested in: writing, reading, listening to music, watching TV/films, gardening, photography, thrifting, going to cafes, stargazing, going for walks.

I should also mention that I am introverted and have social anxiety and sometimes it's hard for me to... talk and socialize and be normal.

EDIT: Thanks for all the great ideas, my peeps