No matter how much sleep I get I'm always feeling tired?

Okay, so diabetes does run in my family and so does "low iron" etc etc. But I can sleep for hours and still be tired.

There's an app called Sleep Cycle for iPhones and maybe others that's great for this. It senses your movement when you are sleeping. When you sleep you enter Non REM so you aren't in a full deep sleep. After about an hour of being asleep, you enter REM (Rapid eye moment [it was called this because during this time your eyes constantly more because when you dream, your eyes actually move like the dream were real life]) which is the deepest sleep where you have dreams. After that, you go in and out of REM and non REM. Most regular alarms wake you up when you are not in your lightest sleep so you feel tired, but Sleep Cycle has a 30 minute time interval alarm so if you set one for 6:30am, it will wake you up between 6 and 6:30, whenever you happen to be in your lightest sleep. It helped me a lot so I don't feel tired when I wake up and it might help solve your problem at least a little bit! And it's only 99 cents, but I'm almost positive you can get a free one which is only good for three nights or something.

See your GP and have the blood tests for the iron and diabetes, also an underactive thyroid causes extreme tiredness.

Go get a CBC. (Your doctor will have to order it.) If you are deficient in anything this will reveal it. A lot of people are tired because they don't get enough exercise/activity. Others because they don't eat right. In other cases it's depression. If people are deficient in iron in your family it's because they don't eat a balanced diet. If they are diabetic, they should exercise more and watch their sugar intake and keep their weight down.