what are the signs and symptoms of diabetes?

I was just wondering what are the symptoms of diabetes. Could these be any.
1) I sleep 12 hours and still really tired when i wake up.

2) I'm always cold.

3) Ive got very bad circulation.

4) I go to the toilet at least 2 times at night (pee)

could these be any of the signs . I'm overweight 19yrs old but i'm on a diet ive complety cut out all sweets, chocolate, biscuits ect.

thanks for any advice xx