I have read that it does no harm at all ~ in fact there is no need to take a break, although some women prefer to have the break as psycologically they like to know they aren't pregnant by having a period.
I think I red this in an article by Hillary Jones.
I read something similar but also read somewhere else that they recommend you try to have approx 4 breaks a year. Not sure why though. Think the longest I have done is three packets in a row.
No it won't harm you.
I've been on the pill for 6 years and have done this many, many times before. At worst you'll get some spot-bleeding and your periods might be heavier and more uncomfortable when you do eventually have a break.