In answer to your questions:
1)After ovulation, you have your Luteal phase which will end in pregnancy or period, dependent on if conception has taken place.
2)Your Luteal phase is a fixed time. The usual for many women is 14 days, this may be 13 - 15 days dependent on when ovulation actually took place , morning evening etc. as pinpointing ovulation precisely is very difficult. The range of normal LP is bigger, 10 - 16 days would still be considered ok by most doc's, but should only vary by a day either side for each woman.
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Yes both my mum and my sister had one pregnancy each where they did not get positive pregnancy tests and were pregnant. On their other pregnancies had normal pregnancy tests. Blood tests will not necessarily help here, would need to be scan eventually.
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The most obvious cause of you not getting your period is that you have not actually ovulated. You can't be sure from opk saying high that you have definitely ovulated, it just means you had raised LH, which may or may not trigger ovulation. So unless you had a scan to confirm ovulation, (or you have a very clear biphasic BBT chart), then you cannot for certain say you have ovulated. If you really normally did ovulate on cd22 and were getting af on cd29 then a 7 day LP is a concern! Ovulating on cd 22, with a normal 14 day LP would mean that af would not be due til cd 36.
5a) If you have not actually ovulated (which seems possible), one of two things will happen, you will either have an annovulatory cycle, and may get a bleed around the time your next period is due or later. If it is much later then seeing a GP, they may suggest taking the pill to jumpstart your periods might be a possibility, they may take blood tests to see where your hormones are at. With an annovulatory cycle opks are useless.
5b)The other possibility is that you might just be ovulating late this cycle. So it might have occurred after cd22, continuing to use opks may or may not have helped. I personally don't trust opk's!!!!
When you say you have been tracking everything - what do you mean?
Do you know when you usually ovulate or get usually get positive opks?
Do you temp BBT?
Do you track CM?
Have you had any hormone blood tests?
Is this your first month of tracking your cycle or have you previous cycles to compare with?
In the rare situation of you being pregnant without a positive test there are the considerations that need to be taken, the first is the possibility of an ectopic pregnancy, which is obviously very serious. The second is that all would be fine but frustrating, because doctors will not believe you for months - as with my mum and my sister!
Sorry this is so long, but wanted to try to answer your questions.