Possibly Diabetes.....???

It really depends on what sort of test you had, when it was and under what conditions. It's better to wait to see what your doctor says.

We can't say if It's likely or not. You need to see the result of your fasting BG. The one fasting test still won't confirm if you're diabetic or not; for that, they need 2 separate fasting tests over a certain level. Or, they may, if your fasting test is high, send you for another different test called an "HbA1C" which shows what your average sugar levels have been over the previous 2 or 3 months. Then they will be able to give you a solid diagnosis. Things like infections can temporarily raise your sugar level, but the separate tests I mentioned above are designed to remove anomnalies, so if they say you're diabetic, you need to accept you are.
Regarding you not being overweight - lots of us aren't. It's the media that labels all diabetics as fatties. About 20% are not overweight at diagnosis. I wasn't. Don't panic though - it's not the terrible sentence you may think it is. Sensible action on what we eat and when we exercise means that many of us control it without drugs and with little or no effect on our lives. So come back when you heve your results (whatever they are) and we'll be able to give you more info. By the way, make a careful note of all your results, and what units they are in etc (what kind of test) - it will help you in the future.
Good luck!