As others have said, where you set your counter is a personal decision. I will share one thing the psychologist talked about in our group in rehab. She said there are "slips" and "relapses" She defined a slip as a mistake, contained to more or less 24 hours, which you immediately realise is a mistake, care that it is a mistake and immediately reach out for help for- which you did by coming here. A relapse she defined as a period of continued drinking, during which you have a "I don't care" attitude about the drinking and do not reach out for help.
Going by this school of thought you slipped up GF. Get back at your sobriety to prevent this from becoming a full blown relapse. Again, as for how you count your days, that is up to you. I personally would want to be fully honest.
We are all here for you. Let go of the girl and concentrate on yourself. Start going to gallery openings or book readings or concerts- cool and cultural events where you will meet beautiful women and interesting friends who are not just in a place to drink.