What Are The Side Effects Of Yasmin?

i am on yazmin pill and i have decided not to have a break in the pill this month as i am away at a festival this weekend and the idea of being on my period and not being able to wash as i would like to and have the toilet facilities ideal for that situation caused me to make this decision. will this be ok? my mum said it's something that won't hurt although i am expecting my period to be slightly heavier/longer than usual when i do come on. is this the case and are there any other worries or concerns i should think about?