Sorry, I am really into running, it has changed my life so much and I am just trying to help. These are the things I said and say to myself to get to where I am. I have been getting more and more ash like, at least in my personal opinions (just do stuff, basically, don't let things get in your way-whatever it is that you judge yourself by, our politics are still crazy different I'm sure.)
Seriously though, my advice is just to make yourself proud of what you are doing (like, really really proud) and you will enjoy it more, enjoy your life more, etc... It is easy to tell when you have done enough because you will feel great about yourself. The only time you have an injury to worry about is when you literally like can't walk or something. I've tried to run while injured a lot. It is also easy to tell when you are injured and not hurt or sore or whatever- you will just know. Pay attention to your body, you will have like a breakthrough type thing (it isn't a "high"- it isn't that pronounced) that is good. Pay attention to your body, you absolutely cannot run even though your mind is determined to- that is bad, that is an injury. Make sure that your mind isn't controlling your body- that should get easier to do the more you like running, which should come with running for pride.
I wasn't trying to call you a whiner, that is not what I was thinking or trying to say, but the things that you say completely conflict with what my advice is, so you do have to stop doing that (well, you don't, but that is my advice.) Seriously, do it to make yourself proud and you will eventually love doing it and all of your other issues will fall away- you will know when enough is enough, when you are hurt, how you are doing, etc. On the other hand, maybe I just had something in me that makes me love running and you could never take my advice because it just won't work for you. In that case I would try other cardio things, swimming, biking, whatever, and maybe you love that one and can get to the place I am telling you about with one of those activities. But seriously, I urge you, just try to follow the second paragraph of this post for a few months, then maybe you will understand how I am not being an asshole. Oh, also, I was not athletic either, was an alcoholic coke and pot head for like 6 years. I have smoked cigarettes and weed everyday for 13 years now. You can do this.