Breakthrough bleeding on the pill? anyone ever experienced or know anything about this?

I know I just posted a question not long ago but now I am stressing out about the breakthrough bleeding. It's only the third day of the bleeding and it is like a normal period now. As I said before I have skipped my sugar pills 3 times in a row now (I am taking Levlen) and the bleeding came 3 days after I started a new pill packet taking the BEIGE pills, I have no skipped or missed any pills apart from the sugar pills. I am worried this breakthrough bleeding is going to last a long time as I think that would have an impact on my life in my relationship. Has anyone ever experienced this? I have a doctors appointment tomorrow. Any answers greatly appreciated