As a biking diabetic let me first say...GO SEE YOUR DOCTOR and write down all your sypmtoms before hand or any your girlfriend may have noticed.
That said I prior to my diagnosis (I'm type 2...less severe). I was having fatigue problems but also I ate nothing but crap and had little activity. My main cue was that I was voracious in my sugared drink consumption. One night I mixed a gallon of lemonade and drank it all in 15 minute and I still could have had more (that pretty much sent me to the doctor). If you're thirsty for sugar all the time...peeing several times a night...waking up with about 4 seconds to pee. You "could" be diabetic...the sooner diagnosed the better. If caught early enough it can be managed by diet. So write down all the things you're feeling and check with your family if there is a history. THE GOOD NEWS...biking is good in helping to manage it. I wish you the best.