Spotting a week before period. HELP?!!

Ashley
First things forst, I'm on the pill. This is my fifth month on the pill. I'm supposed to get my period at the end of this week (last active pill is Thursday), but I always get my period Sunday (I have period cramps five minutes before I get it). 
Today I felt similar cramps to those of my period and I thought it was a bit off. I normaly always have a lot of discharge but when I was getting ready for my shower this afternoon I saw something was off. My discharge was dark brown. As I wiped myself, I noticed my discharge had a bit of blood. But no brown colour or blood has occured yet since.
I am sexually active but I've been more on time with my pill this month than usual so I don't see why I would be pregnant, especially considering he always pulls out. 
I'm scared. All my friends on this pill say it's normal and it's happened to them. They're much more reckless than I am when it comes to peotection and taking their pill on time, yet they always get their period. 
I'm on Alesse by the way. Can anyone give advice please????