Could be, as mentioned, that people weren't sure what to say, or weren't sure what the reason for the weight loss was. "You look fantastic!" isn't so good when one has just had a serious, debilitating illness LOL, and if they haven't seen you for awhile they mightn't know your health history.
As one who cut her rump length hair a couple of years ago may I encourage you to NOT let anyone talk you into cutting yours if you have any doubt about the results? I like the shorter length well enough, but not as much as I liked it long, and am letting it grow again. At my age though I am not sure how successful that will be. (Down to almost mid-back now, so there is hope)