bleeding through bc

I have been on birth control for years, and I've been on this same one for about a year. I used to always start like 3 days after the pills ran out, and everything was very much on schedule. I never ever bled through my pills even if I forgot to take it like 2 days in a row. But here lately I just will randomly bleed. It's like if I normally take the pill at 7 and haven't taken it by 7:30 I start bleeding. And it's not really fresh blood it's like a brownish pink color and it's not super concentrated it's like diluted. Also I have been having an excess amount of discharge lately and I've felt for a little while that something was off down there but I can't figure it out. Any ideas?