My hair has been falling out loads, especially during winter, when they come out i see white /yellow stuff attached to the roots and scalp, what is it?

Many possibilities: Hair "turns over" faster than just about anything else in the body, and many things - from illness to injury to surgical procedures to hormonal imbalances to infections to stress - can interfere with the normal hair cycle. Don't waste your money on tonics and "hair vitamins". Let a dermatologist go through the possibilities and find the cause. (the yellow stuff on the roots is normal.).