How long does it take for your period to come back after you stop taking the pill?

I was on yasmin bc pill for about 7 years. It has now been five weeks and still nothing. I have taken a couple pregnancy test and they were negative. My husband and I want to try to conceive but I need to have a regular cycle again before I can switch our health insurance. When should I start to worry if nothing happens? Is there anything that I can do to try to get it back on track>