I am 20 years old. And i never really had a regular period but on averae it was between 28 and 30 days apart.However from April my period came 20 days in between, then 21 days in between, now its back with only 15 days in between the start of the last and this one. Not only that, these periods have been long, lasting almost 10 days. They arent heavy though, they range from light to normal. Also they are different in colour, very dark brown and watery, then it usually goes back to its normal color and viscosity. What is wrong with me?