The pills does all sorts of strange things to ur body, years ago I went through 3 types/brands before I found one that didn't make me sick

But my thoughts would be that AF will not arrive until 28 days roughly after the last bleed as the drop in hormones would of restarted your cycle causing another period to occur so AF may be likely to show around 1st jan going by your dates?
The only way you can rule out pregnancy is a bloodtest just request one from your gp, good luck