hypoglycemia or diabetes?

hi everyone...at first i didn't think much about this little problem but now it's starting to get on my nerves...my 1 year anniversary was may 16 and i have lost almost 140lbs...(10 lbs below goal weight) in the past couple of months it seems like my blood sugar is going haywire! it seems like i have to eat every 2 hours or so and if i eat too much sugar (no dumping for me) i feel like i'm going to jump out of my skin! is it possible to develope diabetes once you lose all your weight? i guess you could say i exercise excessively...i walk 9 miles on the trail 4 or 5x a week (36-45 mi total a week) and do an hour of circuit training and/or aerobics class 3 - 4x a week....i try to get in 1800 - 2000 calories a day....anyone else having these problems? thanks lizzie