That sort of thing happened to me when I was drinking, also in the hangover phase when I was not directly intoxicated. I would also sometimes switch letters within words in writing. Found it very annoying - the cognitive effects (among many others) were some of my main motivators to finally decide I should quit for good. I think I have personally been doing this much less frequently since about 1 week into sobriety. I'm still only ~1 month, perhaps there will be phases when it comes back later? We'll see.
One of my close friends in the past was also an alcoholic and we wrote many emails and IM messages to each-other all the time for years intoxicated, hangover, feeling OK, and everything in between. I noticed many similar errors in his messages.
Like others said, this should get better with time. I would also suggest paying extra attention to nutrition, probably many of the nutritional deficiencies associated with alcohol abuse are at least partially responsible for impaired cognitive functions.
Guess we just need to tough it out
