I gained nothing until about half way through when I had a sudden jump in weight. Overall I gained about 10kg I think.

From memory, for an average person of healthy weight you'd expect to gain approx 12kg during pregnancy. My OB said about 1kg gain at each visit (visits get closer as the pregnancy progresses so weight gain speeds up a bit). My gain pattern was all wonky but he wasn't worried, and neither was I! Bub was healthy, I was healthy, so nothing to worry about