Hi Sweetpea, don't panic
I don't know what went wrong, what changes took place in your body but for me yes, shorter cycle always meant high estrogen and very low progesterone. This may or may not be the case with you.
Only you can tell what's wrong with your cycle, start measuring your temperature (BBT charting) and will be able to tell yourself what's wrong. At the moment not even doctors will tell you what went wrong. This is why I keep repeating how important it is to start monitoring your BBT when you start PM. With PM it's not that simple. You were taking it 15 days but why 15? Why not 13 or 18? If you wanted to copy Chiyumilk's routine then you were supposed to take it until about ovulation time. Do you know when you ovulated? On day 15? Some women ovulate on day 14, some - on day 8! So without blood tests and ultrasound you won't be able to tell when you ovulated and what your hormonal status is today. You can try and help yourself by at least getting your chart. These charts are very easy to do and you can read and I'm sure you'll be able to read them yourself or you can ask me or somebody else on this forum.
About overdosing. In my opinion yes, you overdosed. Even 4 pills a day is really A LOT when it comes to Siriporn. I find that their PM is stronger than St.Herb, for eample. This is why they recommend a lower dose. I was taking 1 in the morning and 1 in the evening and still my cycle was shorter. Taking 8 pills a day in MY opinion is bad. I don't know how much damage to your own body you've done, you can consult a doctor. But since it's only has been one cycle then maybe you can try and repair things yourself by not taking PM orally, just use their cream (which btw is also very strong, so, don't overload on that too).
More doesn't mean better! In NBE it can even be dangerous!
If you want my theory about what went wrong then I can tell you this. I think you were supposed to ovulate before you stopped PM. Let's say on day 10. You continued taking PM and kept your estrogen so high that it cancelled ovulation. No ovulation -> low pregesterone. Then you stop taking PM, your estrogen level drops a little tricking your body to believe that this is a pre-menstrual drop of estrogen and - voilà here comes your period. This is just MY THEORY. Purely based on my own research and other user's complaints.
You really should stop overdosing on PM, do your BBT charts and see if you ovulate or not. Usually it will regulate itself in a few months.
I will copy this post in PM thread. I want others to be warned too.