I don't see how this is an issue. As a mathematician I get most of my actual work done in some kind of intoxicated state. If I'm not intoxicated and working I'm on some other substance. My work doesn't suffer...
Some people do thrive on a personally suitable level of intoxication, I used to find it far easier to work after a beer or more preferably a smoke.
That changed over the last couple of years and now even a small drink or smoke leaves me unable to work properly for at least a day afterward, and I had to change my habits.
To the OP I say you've hit the first step, you've realised that something you do is having a negative effect on your life, whichever way you choose to make a change let me just say it is worth it, and if you have a couple of people to share it with it wont be difficult.
I suggest that if you find somebody you can talk to frankly at the times you struggle just having a chance to whinge will make things easier.
And if you're physical health is suffering, as people said, go see the doc.