These are some prominent sypmptoms that I've had for a while (I'm 17 years old now) and I've been wondering if any of them could piece together to be Diabetes or an Underactive Thyroid...

-Low tolerance to the cold. I get cold hands indoors very often, even if the room I'm in is warm. In the winter, I can often only stand to walk around the house if I have a large blanket wrapped around me.
-My weight. I most definitely eat normal portions of food, and in most cases less than my peers (I actually have a really big appetite, but as a result of taking Adderall for my ADD and my constant struggle to hold it down I don't overeat). Despite this and my struggle, I am at least twenty-five pounds overweight. Before I took the Adderall I was 40 lbs overweight.
-Depression, though I am not on any medication for it now and have not had any problems for two years.
-Thirst. And no matter how thirsty I am and how much I drink, the water just seems to go straight through me and I have to urinate ten minutes later.
-Weakness, fatigue
-Strange stomach pains that doctors can not find the cause of. They strike for about a week-long period every other month or so.
-Very irregular menstrual cycle. Sometimes I will skip a month completely.
-Sudden but fleeting joint pain of the back, hips, knees
-Bad memory
-Constipation

I have a very bad family history of Diabetes (3 of my 4 grandparents have had it).
When reading a list of symptoms for a hypoactive thyroid, I can relate to all of the symptoms EXCEPT dry skin. My skin is quite the opposite -- very oily.
I have had a blood test to see if any hormone levels were abnormal in my thyroid, and although the results came back normal, my doctor said it was a very broad test and didn't completely determine whether there was a problem there or not.