Well, Hana, after reading your story, I have to say, I am not tall. Well, not compared to you anyway. I am only 171cms.
I can't believe the nurse in your GP practice. Fair enough, she didn't know how much weight you have already lost (so maybe you should give her some info on weightloss), but to be honest, 76 kg is not a lot at your height. Why on earth do they make comments like that based solely on your weight? Doesn't she have eyes? I'm sure you don't look unhealthy with all that exercise and weightloss.
Another thing that gets to me is that they always seem to think that if you're overweight it's either because you're just simply too lazy or too dumb to do anything about it...