Why Am I Not Having A Normal Period After Stopping Birth Control Pills?

I have taken my birth control for 3 months at a time. This is the first 3 month cycle that i have done and i stopped taking the pill at the end of the 3 months and my period is very light. I have clotting and spotting but no real period. Is this normal or is there a chance i could have gotten pregnant. I take my pill every day at the same time and never missed a pill. Please help. I cant get a hold of my dr. to ask her and i am wondering why i havent gotten my period yet.