It's a good thing to seek help, from SR and elsewhere if you choose, to get the aid of a grief counselor. Drinking will only feed the grief that you are experiencing, and it's not going to be good for you either in terms of your own life. From how you are consuming now, I don't think that just getting the aid of a therapist is the only thing you need.
Now that you are coming here to deal with the Vodka that is eating at you, the best thing to do is to stop drinking it. You then have two positive things that you are doing to address how you are living now, both good starts. The intensity of the grief should be subsided without the booze, and you will be less vulnerable overall.
I know what it is like to lose a father, it happened to me last month. Join me in a clear headed way to remember the beauty of your memories and to allow yourself to find a path that will take you forward instead of stagnation and pain. You will feel better in time.