Weight and Birth Control Effectiveness

Hi! I am in my second month on Estrostep FE and I like it, despite moodiness and constant breast tenderness (I hope these side effects will go away, but if they don't, it's a small price to pay...).

My post has to deal with a post from much earlier on in this forum - the one concerning birth control being less effective in women who are overweight. I read that and almost went into shock. The post read that women with a BMI of about 30 or above are at risk for this, and my BMI comes to 28.

Should I seriously worry about this, or am I protected? My boyfriend and I are committed and have used the withdrawal method on top of my birth control, but maybe we need to revert to condoms....?

Thanks,

-Molly