What Causes Brown Spotting Between Periods While Taking Contraceptive Pills?

i forgot to take my pill for two days 2 weeks ago so on the friday i came on my period (lightly) so i decided to take the week off the pill. But then on monday i read on the booklet that came with the pill that i should carry on taking them if i missed some. so from monday i kept taking the pill but i had brownish coloured discharge... and by this tuesday it was like dark red and thick so i decided to stop taking it again and have a propper week off but how long will it take till i come on my period properly and how long will my period last? :'(