My life experiences might be pertinent to your current issues, so I'll do my best to at least help you even a little bit.
First of all, I think it is very likely that H itself is the root of all your issues. If you use dope regularly, it becomes really difficult to cope with everyday issues without dope. Because anything that you have to do becomes so much easier and carefree if you are high. This in turn leads to a situation where if you aren't high, you are not able to deal with with your emotions and daily activities.
The only way to stop this "Catch 22" situation is to stop doing dope. And this can be really hard to do as I am sure you know. Like I mentioned before, chronic H use can make the struggles and even joys of 'regular' life seem bland and pointless. So initially, you will have to deal with anxiety, sadness, depression without running away and hiding the in bland, suicidal, falseness of heroin. But you got to tough it out and try and manage. And once you tough it out and try and get used to learning to deal with life without H, the feeling of achievement will give you a feeling not unlike H. So the first think you need to do is decide for yourself if you truly want to quit. You have to give it your best or it's just going to be a waste of time.
Once you decide that you really want to quit, you should first of all try and rid yourself of anything that will remind you of dope. Stop hanging out with other users. Delete all your dealers numbers. Avoid reading about H use on the net. Secondly, try and find something that will add structure and substance to your life. Something that will allow you gain that feeling of achievement without the dope. The best option for that is to play some sort of sports or start going to the gym. It's the best thing when you are recovering from drug addictions. Make some new friends with non-drug interests, start going to art museums, read a book. Basically keep yourself busy so you won't have time to get depressed and start craving dope.
Peace man, I wish you all the best!