Do i have diabetes??

[Bubba]

I've been experiencing some odd weight gain recently (i'm not overweight). even though i've been keeping a stable diet& exercise regimen for a short time now (i try to eat veggies and fruits everyday, and do 45-minute walks everyday), i still notice my waist &legs expanding (i even measured to check if i was just being paranoid, but i was right).
my mouth has also been unusually dry, so i thirst, drink and pee a lot in effect.
i also noticed a tiny wound that's been taking quite a while to heal.
i've been feeling tired a lot (fatigue?) and my stomach started feeling funny just a couple hours ago, which resulted in excessive eating (i had about three platefuls of shrimp &clams,then my body was still looking for more & i somehow i got attracted to the jello in our fridge so i had a bowl of it,and after that my stomach still felt odd as if it was still missing something, so i had a couple crackers. i still didn't feel satisfied after that, but stopped eating. i still feel like crap now.)
okay. does this automatically mean i have diabetes, or do i just have high blood sugar levels (which can be remedied and lowered)? i'm really scared because i haven't been eating a lot, even trying my best to incorporate fruits and veggies into my diet and exercising regularly, but haven't been noticing any reduction in weight or size (just increase, or nothing at all).
i'm scheduled for a blood sugar fasting test two days from now.
i'll be 19 in july.
how do you notice sweet-smelling urine?
why, do polyuria and polydipsia automatically qualify someone as diabetic??????
only my aunt has diabetes...well, as far as i know anyway.