ideas come from interaction with others. if you sit at home alone all day, nothing new can enter your world. drugs make this worse because they keep you from experiencing life, i bet you do them out of pure boredom.
so just find some shit to do and interact with other humans. set minor goals, like run 2-5km a day, read 150 pages of good book a day, etc. get your auto license. learn shit, any shit youre interested in. take a holiday somewhere warm and sunny. find a sport/activity you truly enjoy, and go train it at a club - there you can meet people you already have something in common with.
it's hard, but it's way easier as it seems. breaking the ice and actually doing something new takes a huge weight off your chest. as for anxiety... noone likes jumping in cold water, but the swimming makes it worth :)