What is going on with my baby?!

cZa

My baby has always been an excellent nurser and took well to a bottle of pumped milk when I went back to work. I have only given him a bottle personally a couple times. The past 3 nights when he wakes up, he is refusing to nurse. I got him to settle down by taking him into the family room and he nurse a little bit. He has been screaming until DH eventually takes over and gives him a bottle. He is nursing fine the rest of the time just refusing during the night. What is going on? Is getting over nursing? I am feeling down about this and feeling like my 1 year goal is going down the drain.