C.G.
Weight leveling off is totally normal as they get more active and have less interest in sitting and eating (or nursing). He probably did lose a bit from being sick- I know I always think of that as the one benefit I get from being sick. Obviously he is growing because he got taller.
As for weaning, only an idiot would suggest you take away the best source of nutrition available anywhere;) I try to impress upon people that cow's milk is the breastmilk of a cow made for a calf so why would it be better than breastmilk from a human made for a baby? Keep up the good work!
(By the way, I am not even an "extended" breastfeeder myself, I just recognize the benefits)