If you are losing your hair is a "V" shape, it probably is not related to stress. If you are concerned see a doctor for a proper exam. There is a reason they call it male "pattern" balding.
In general there is no pain associated with alopecia areata. If you are concerned you need to see a doctor for a proper exam. There is not much the Internet can provide aside from general information.
No, there are no definite statistics.But individuals with telogen effluvium from fever can lose 40-60 % of their density.In a pure (classic) TE, hair sheds 6-10 weeks after the illness and continues for another 4-7 months. Hair grows back by one year.Be sure to see a dermatogist for evaluation...