I have a friend on anti depressants and she mentions the same hollowness and lack of wanting to do anything - despite having a good social life.

When I went through depression I refused meds, self medicated with weed (don't take it as medical advice) and got through the end of it.

I'd blame the meds and recommend gently weaning off them. Once you feel better rebuilding a social life is absolutely possible.

Best of luck with everything