Just started breastfeeding is it possible

I'm about 3 weeks into it and one of my breast just stopped milk . Someone did mention to me to use the weak boob first while breastfeeding but hardly anything would come out and my baby was getting fussy . So I started pumping BARLEY getting an ounce out , then to drops if I squeezed my boob . Now nothing :(

Can that happen ? Can it be possible that I have no more milk coming thru that boob ?