Im 15 years old. I usually have really heavy dark red coloured blood periods and I have been on my period for a year and a bit. Suddenly during my last two cycles, my periods have been very weird, my blood seems to have changed to a dark brown/light brown colour and it does not turn red and it is reall light. My periods usually last 4-5 days, but recently they have only been lasting 2-3 days. I am not sexually active and have never had sex. Please help, I'm really worried x

Don't worry about it,
When I first started my period, it was really heavy and dark too, your body just doesn't have as much old blood. Its perfectly normal. If you have further concern talk to your doctor.