Do staying in the house cause pigmentation changes?

Hi, Im 22yrs. old i ust to be very dark skined when i was younger n unlike others i adore my color, now the problem is i went from dark to pale, to brown skin, to light, to dark, to pale n ex... im realy weary n afraid sum'n is going on with my skin pigment can someone please tell me what they think is going on, oh i have anemia as well do that have anything to do with it? please help.......