I would suggest expanding your support group ( great idea not hanging around the old crowd BTW), picking up the phone, hitting another meeting, writing a gratitude list and/or bucket list and doing some of the things you couldn't/wouldn't do when you were drinking.
You've started a new stage of life, and while the 'blues' are definitely a part of it, especially in early sobriety, your free time need not be ruled by them.
Congrats! on 3.5, it only gets better!!!