A motivation within it self should be to fix the way you are feeling. You can still smoke weed and have a productive life, despite popular belief. I suffer from having very few friends as well, and it's hard when you're lonely and all you want to do is be happy and feel the high that you get. What are some things that you enjoy, other than smoking? It could be as simple as, if you like nature, go for a random trip to the park. Shake up your routine with something you might not normally feel like doing, and you will be surprised with how rejuvenated it makes you feel. Also, it might sound lame, but sites like okcupid really help with meeting local people (even if just for friend purposes). I hope you start feeling better, honestly. I suffer in some of the same ways you do yourself.