Do not take Plan B while on the pill!!

I see this all the time
If you take it on time everyday and never miss you do not need to take Plan B!
Most pill brands say you are still protected if you miss one day, but check your packet. There is no reason you would ever need Plan B while on the pill unless you literally missed 3+ days in a row. 
Plan B = about 3 days of birth control. Taking Plan B + your regular pill is like taking 4 of your pills at one time. It's unessesary. It will mess up your whole month and will give you horrible side effects and make you bleed. 
I just wanted to put it out there because it seems some people have no clue how birth control works or how Plan B works. 
Edited to include Anonymous's comment as to why: