Confused!?!?

So I just started using glow about a week ago or so and I went back today in my old period app that I was using for the last 6 months. I averaged my periods out and put in my new averages and also put that I am irregular by 5 to 15 days. Now it says I should have started my period 4 days ago.i have yet to start and I have had a little cramping with some pinkish/brownish colored discharge. (Sorry if it's tmi) I'm just not sure what to do. I also started taking vitex yesterday so if any one has had a good experience with it and would like to share I would be so greatful to hear about it.