Hi Lurudolph,
Yes, that's a pretty low score at your hip. The other ones aren't too bad at all. Your weight loss could have something to do with your bone loss. On the one hand, lugging all that extra weight around put pressure on your hips, which kept them strong. Once you lost the weight, those bones didn't need to be so strong any more. On the other hand, maintaining a healthy weight will extend your life, so good for you for losing the blubber!
If I were you, I would ask for a referral to an endocrinologist. They're the ones who look at all your metabolic systems and can recommend a course of therapy. Are you getting any exercise? Do you take extra calcium? Does your diet include good sources of calcium?
There's an excellent site on bone physiology that has lots of information on osteoporosis. It has a page that explains what the DXA numbers mean, another that shows all the different treatments available, and lots of little animations of how bones are remodeled. If I were you, I'd bone up

on all the info before going to see the PCP.
Copy and paste:
courses.washington.edu/bonephys