Seasonique

I was attracted to Seasoonique because of the whole 4 periods a year thing. I am nearing the end of the fifth week on my first pack. The first couple weeks were great, no spotting or break through bleeding, (even now I have yet to have any spotting/btb) and the only side effect I noticed was a slight acne breakout. Now, for the past couple days I have had moderate nausea, slight head aches, mood swings, and some cramping. I know these are all expected side effects, but I have also had very bad back lower back pains. They really come and go, but when they come, they hit hard. So hard to the point to where I have had my four year old son walk on my back, (much to his delight). They are sporadic throughout the day. Has this occured to anyone else? I have read some other blogs and have encountered a handful of people with the same symptoms, but I guess I just need a bit of personal assurance.