Oh dear
Well to hopefully answer a few of your questions...
You do have signs that will tell you when you O, but unfortunately usually you need to start charting and chart for at least a few cycles before you can begin to recognize what your personal signs are.
If you want to start charting...GOOD FOR YOU! I think you will ike it (as long as you don't obsess. That's the hard part) You should buy the book Taking Charge of Your Fertility (
www.ovusoft.com) It is AWSOME and it explains everything fertility. It will help you get a handle on what's happening with your body.
You could start to chart whenever you want. You just have to start a new chart the first day of AF. I suggest you chart online at
www.fertilityfriend.com that way when you have a question it's easy for us all to see your chart and help you answer it.
If you start charting tomorrow morning, there is a good chance you will know when AF is coming about a half a day before it does because your temperature should drp suddenly right before AF comes. But this is not a hard cold fact...it's a probability.
Also if you start tomorrow, and you haven't O'd yet for whatever reason, you may still be able to catch it! (even better

)
And if you are having a stressful time right now, that could explain why your OPKs were different this month. When you stress out you can lengthen the time before you ovulate. No worries...you can try again next month!
AND as far as the jeleousy goes...hunny welcome to the club! LOL
Good luck, and don't spaz out too much