Breast milk

I hadnt breast feed or pumped in a month, November i took a break bc i decided i wanted to drink alcohol here and there, especially with Thanksgiving, my baby took formula like a natural.. however, now i feel like crap bc i practically lost all my breast milk. I could hardly get an oz. I really want to breast feed my baby again, hes 4 months. Is it possible for me to get it back or am i fucked? Ive been massaging, plenty of water, dont eat junk food. If i cant get it back, its fine, i just want that bond again..