All of a sudden? yasmin. ugh.?

I have been on yasmin for about 4 years and never ever had a problem. the past 3 months, whenever i get my period and a day or two before, i get SO tired to the point where i have to take 4 naps a day. my period makes me feel horrible. This has never happened to me before...im wondering if i need to switch pills? or is this just something that can happen over time? any help or advice is appreciated =)