Sounds to me like you have PTSD as a result of combat, and you are attempting to self medicate with the alcohol. This is typical of myself and so many others.
You might want to get a non-VA phycologist or physychiatrist who specializes in this sort of thing to examine you and write up that you have these symptoms as a result of combat. Sounds like you have lots of proof that your unit saw action, but do you have any proof that you were actually involved. Might need buddy statements.
If I were you, I would file a claim for PTSD immediately, and use the services of a reputable claims processor such as the DAV, VFW, etc. to help you.
After you are awarded the PTSD, then you can apply for alcohol as secondary to the PTSD.
I have gone throught the inpatient program for alcohol, twice, and it is helpful. Also there is the PTSD group at the VA that you should probably join.
good luck