Why does my urine smell?

Diabetes runs in my family. My grandma and grandpa and my mom all have it. None are insulin dependent. A few years ago my doctor told me I was on the verge of it, watch diet, and all that good stuff. I was almost 300 lbs then. I have since lost almost 100 lbs, and I am just not starting to get the symptoms of it. Sweet smelling urine, and when I haven't eaten I get grumpy, but who doesn't? My doctor cant answer why I am getting these symptoms NOW after LOSING weight, and I was fine when I was more overweight? Also, for years I was able to donate blood, but again since losing weight, my blood pressure has gone up, and so has my heart rate. Why am I so unhealthy now since losing the weight??