COULD i have diabetes?

[Alice S]

i know people ask this all the time, but i suppose i just want someone to reassure me :-) Im a 16 year old girl.
I'm worried i may have diabetes because i've got a lot of the symptoms! the first and formost problem being i've got to pee ALL THE TIME! i can ignore it and then suddenly it's so urgent, i'm running for the bathroom....i'll be galloping up the stairs and (sorry...kinda gross) it feels like i'm holding it in, and then i'm not! sometimes i pee for what feels like forever, then other times i'll have the same feeling and hardly pee at all. i thought this might by a UTI, but now i'm not sure....
secondly, i've been so thirsty. i drink a lot anyway, i've been getting headaches too. In bed at night, i get so hungry it hurts but then it's gone in the morning. i've lost a little weight, and i'm 5ft4 and 118llbs s. But most concernedly, i've found myself not being myself. i yelled at my best friend today for no apparent reason, and i've been feeling really moody. it's not periods!
a few days ago, i was in the bathroom, and i suddenly had a really servere pain in my stomach and chest - so bad i fell over and curled up instinctively. I have asthma, and have had this pain in the past prior to an attack, especially if i'm hungry. but this was a whole new level of pain....i thought i was gonnna black out. i've also had stiff joints (might me relevant). I'm really tired all the time aswell, but my vision is okay. things move a bit when i don't concentrate...more so lately. basically all thses things over the past week have made me wonder. could i have diabetes? i'm doing my GCSE's at the moment, so i thought it might just be stress.