I think that's really over-simplifying things. I also don't agree with the sort of "blame the victim" mentality, down-playing the problem and supporting the idea that if only the person did something differently they would be fine. It's not that easy and no one feels this way by choice. Things like this, whatever you want to refer to them as,
are caused by an imbalance in the brain. Now that
doesn't mean there is nothing that can be done or that environmental factors - past and present - don't play a role, or that it is hereditary, or that prescription medication is the only option (in addition, anti-depressants etc are not a magic cure and can create a lot of problems of their own so should be considered very carefully).
Having said that, from what you, the OP, said, it sounds like it's very possible that you could actually have ADHD. "Anhedonia" basically means an inability to experience joy or pleasure. Anhedonia is a
symptom of some other problem, whether in the brain or the body or both, it isn't a disease. But you said that you feel bored a lot of the time and have little interest in things other than your boyfriend and pot. A lot of people don't realize that they have ADHD because they are not familiar with the symptoms. We don't hear a lot about the symptoms other than what the media portrays about ADHD in young children, but the symptoms in adults and teenagers are can be quite different. The term "Attention Deficit Hyperactivity Disorder" is kind of misleading as well, because you don't necessarily have to have the hyperactivity part, and many people with ADHD don't. I would highly recommend finding a
good doctor or psychiatrist and discussing your issues with them. Medication is not the only way to treat ADHD (nor is it always successful or a good choice), there are many good books etc on how to deal with one's ADHD through natural and behavioural means. Some psychiatrists also recommend certain supplements or herbs, although YMMV and they are very subtle and often take a long time to help. Whatever you decide to do, be prepared for the possibility that it will take a lot of work and be slow going. That doesn't mean it isn't worth doing things to improve your life.
Do you have difficulty doing things you don't enjoy or aren't interested in? Do you spend a lot of time on the few things you do enjoy, to the point of neglecting other responsibilities? When you are interested in something, do you spend a lot of time focussing on it, until suddenly you inexplicably grow bored with it and move onto a new obsession? Do you have trouble with motivation? Trouble concentrating on things you don't like? Do you spend too much time on the computer? Do you have trouble staying organized? If you answered yes to any of these questions (especially given what else you said in your post) I would seriously consider the fact that you could have ADHD. One great and progressive book about ADHD is "Scattered Minds" by Dr Gabor Mate.
Good luck and I hope you can find some ways that work for you to help you live a happier and more fulfilling life