I have been on the pill for years, first with estrostep, switched to ortho-tri-cyclen (trinessa) since there was a generic and was having bad breast pain so my dr. switched me to levora (generic for levlen). I always started my period on a wed or thurs before and now I am not starting til maybe friday. Is this normal? I hate it since it stresses me out and makes me think I am late. Does this mean I am taking a stronger pill now or something? I don't know why my period wouldn't start on the same day it always has before. I have been on levora for 3 months now and no problems yet.