I can't relate to the hair loss but I'm 28 years old and I have so many grey hairs! My hair is naturally dark brown so I've had to lighten it to try and blend them but I am very grey for my age. I do think a little bit of it is genetic but most of it I think has been accelerated by alcohol use. Someone I went to school with had a mini meltdown on Facebook recently about finding her first grey hair and here I am with a million! It's depressing.
A friend of mine went through a spell where her hair was thinning massively and started using a special conditioner which helped. Our hair is so closely linked with our diet though so eating a balanced diet/supplementing for any nutritional deficiencies will work wonders