Did you have a withdrawal bleed after finishing the pack? The first day of that is the first day of your last cycle.
The first day of this cycle is the first full day of bleeding (if AF starts after midday, CD1 is the next day).
I would potentially base it on the first cycle off the pill. If it's going to be 7 weeks long my feeling is you've peaked too soon!
You should OV 11-17 days before your AF is due. Your luteal phase (the time between OV and AF is 10-16 days long, but will be constant, give or take one day). If anything alters it'll be the time to OV, e.g. stress can delay OV, but once you've OV'd your luteal phase shouldn't alter.
If AF is late, it's either late OV or pregnancy, not an extended LP.
So, I don't know when you'll OV as you're not sure how long your cycle is. If you knew that we could hazard a guess.
That's why I've gone straight to OPKs this time. Much easier to work with!
Sorry if it's a bit confusing.
And I'm not too bad. Bit lightheaded, but not as tough as I has been. :-)