Recurrent infections were my first tip off that I might have diabetes - every time I got a cut (no matter how small) it would get a minor staph infection. Every single time. I'd get a papercut and count down the days until it got infected, no matter how well I cleaned or disinfected it. Given my HbA1C, when I eventually got one, showed an average mmol/l level of 10.5%, not a massive surprise!
I guess bacteria loves sugar, and the more sugary the blood, the more they love it (at least that's how I rationalised it to myself).
Since then, my average levels are mostly within normal ranges and I've not had any problems at all. Getting blood sugar under control seems to be the key - and as others have said here that means not eating as much **** and probably reducing your carbs