antidepressents

ive been an alcoholic for 2 years and a while back i tried to quit drinking because i was feeling really depressed and  been prescribed antidepressents i was prescribed efexor before i became an alcoholic and it worked withing 5 days and i felt great but the second time when i stopped drinking and took efexor but in  3 weeks of taking it it didnt seem to be working, i dont understand is it all the drinking i did before those 3 weeks make the depression harder to treat or something.

thanks for your replies