I am so sorry that you are experiencing this pain. Have you started to read some of the “sticky posts” at the top of the forum? Once you start to read about alcoholic behaviors, you will recognize that the confusion and puzzlement you are feeling is a natural response to the crazy, contradictory emotions and behaviors your gf was displaying. There are any of us on this forum who have experienced these “out of the blue” breakups. One day the alcoholic partner is telling you how much they miss you, what a great time they had during your visit, and what a fox you are in the sack and a few days later they are breaking up with you.
Please try not to take this breakup personally. It is not a reflection on you or how you acted in the relationship. It sounds like you were very caring and supportive. I am also wondering if all of the recent stressors in your gf’s life might have caused a relapse. Is it possible that she may have started drinking again? In my case, the breakup occurred when my bf of nine months recognized he had a problem and started going to AA. I hadn’t even known he was drinking excessively. If your gf did relapse and was being advised to put her sobriety first, then any romantic relationship becomes an obstacle.
Her anger and resentment toward you, hiding her cigarette smoking, as well as the blocking and no contact really make me suspect she is drinking again. It sounds like her sobriety is in jeopardy and since all recovering alcoholics are told their sobriety must come first, your feelings, pain and confusion are the collateral damage.
Please don’t beat yourself up about this. While we codependents have our own issues we need to focus on, it is unlikely that you did anything “wrong” to precipitate the breakup. You will find a lot of support and commonality among the posters on this forum. I hope reading other’s posts will help you get through this difficult time and help you to realize you are not alone in what you are feeling and experiencing.