The most reliable way to find out is to go to your gynecologist right after your period so he can monitor when your egg is ready to be fertilized
You can also know your ovulation day by noticing whether you have creamy mucus and increase in sex drive !
If your period is always on time then you start counting from your first period day until day 11 and until day 17
And you have sex day after day in these 7 days
And good luck
Just a note about your comment that your egg white mucus seems to come right before your period starts. This is probably not fertile mucus because that should happen about mid-way through your cycle (approx two weeks before you have your period). Or if it is fertile mucus, than your luteal phase (time between ovulation and period) might be too short to support an egg properly implanting itself. As the egg starts to implant itself your lining sheds (causing your period) and sheds the egg along with it. I have a great book called "Honoring your Cycles" by Katie Singer. In it they also talk about split peaks where you might have mucus, dry up then have mucus again which is common in long cycles. Just some things to think about. Good luck!