I once commented to my therapist that I wished I could "cry myself to death." She then explained to me how/why that is not physically possible, your body won't let you. After crying hard "forever" your body turns it off, wears out that circuit for a bit.

Alcohol is actually prolonging the pain by interfering with your body's preferred method of dealing with the emotional pain of your breakup/boyfriend leaving. It is like breaking your arm and drinking to dull the pain instead of going through the pain necessary in having it set by a doctor and casted, etc. Both ways it will "mend" but if you don't go to the doctor, don't do it the "right" way it will mend badly.