Frequent urination, thirsty, and weight loss - help??

I don't know if I'm just being a hypochondriac or what, but I've noticed these symptoms for the past few months:

Frequent urination (it's gotten worse and it's always clear), often thirsty/dry mouthed, muscle aches, yeast infections, and have lost a LOT of weight. I don't know if it's because I began to eat very healthy (mostly just veggies, fruit, and some protein) or what. Since August I have lost 20 pounds.

I never was worried about diabetes because it doesn't run in my family, and because I'm thin (I know, stupid of me.) Also, because I'm only 20! But these symptoms are beginning to worry me and the frequent (clear) urination is driving me nuts!

any advice?