How do you stop drinking by yourself?

You should be a little careful. Depending on what you have been drinking and how fast you have consumed it, you need to wean yourself down. If you have drunk hard liquor for years in high volumes, stopping immediately can seriously hurt you.

First reduce by 50%. Drink half what you usually drink, for a couple of weeks. See how you are doing. Then you can reduce by 50% again, for a couple of weeks. Then you can eliminate it.

If you are struggling, think about using hypnosis. You can get more information at the site I linked.