Hiya young17
Could you be mody? I was misdiagnosed for years, first they thought I was type one then type two then they weren't sure (my consultant actually said 'I can't diagnose you') then they worked out I was mody (monogenic diabetes). Its a less well known form of diabetes where unlike t1 you can still make your own insulin BUT the message that tells the body to produce a certain amount of insulin in response to your blood sugar doesn't work so the body doesn't know how much insulin to produce. It's purely genetic, on a single gene, but although you have the defective gene from when you are born it doesn't manifest until the teens or early 20s. So you are the perfect age to be a likely candidate. Also this type of diabetes is not linked to being overweight.
I was 15 when I got it and for many years was on tablets then went on to insulin about 10 years ago where unfortunately I have stayed.
It runs in families so if you have any close family members with diabetes that's a strong sign that you have mody but even if you don't, it can arise from a genetic mutation. My mum and brother have it, but no one else so i don't know who my mum got it from.
Many doctors just think in terms of type 1 or type 2 but they are now discovering there are many other, less well known and rarer forms of diabetes.
But if you can't make enough insulin to keep you healthy then you have diabetes whether its t1 t2 or something else.
If you get to see a diabetes consultant, talk to him about mody. Also check out exeter university who are doing a lot of research on this form of diabetes
here's the link:
http://www.projects.exeter.ac.uk/diabetesgenes/
good luck - hope you don't have to wait 15 years to get a proper diagnosis as I did!