galare, before trying other meds, let's try to get you sorted with what you're on - because you haven't been on it for long right?
The main issue seems to be how to sync the P to your own cycles. Why are you taking the P on days 1-12? That's the opposite of what you should be doing. Progesterone is made during the luteal phase of the cycle, so if you are taking it for half the month you should be taking it from day 16-26.
If you bleed, stop taking it and count that as day 1. When you get to day 16, take it again. If you get bleeding (not light spotting, but what seems to be a period and goes on for more than one day or gets heavier), stop taking it and count that as day 1 again. It may take a few cycles to get in sync.
If you have just started a bleed, don't begin the P tomorrow - let yourself have a bleed and shed the lining. Work with your body, not against it. Your body naturally produces P during the second half of the cycle. Give it to your body then.
It doesn't have to be exact, but you do have to roughly take about the same amount as you'd take from day 16-26 which is 11 days of it. So if your cycle is 21 days (say), you would count back 11 days from 21 and start there, day 11. That way you get your full amount of P in during one cycle.