Well, here's an update, FWIW. Sunday morning (CD30) brought a BFN for me, but not much disappointment as I already 'knew' I wasn't pregnant, despite the late-ish AF. But my WTF cycle seemed determined not to give up on its WTF-ness, as bizarrely, I then had EWCM again. So I did an OPK for the hell of it, and got yet another positive. This was the fourth separate, positive OPK of the cycle (all OPKs were digital smiley face ones, so I had no doubt that they were indeed positive, for whatever reason). 
Then Monday morning AF started. I made a mental list of reasons why I ought to be glad I hadn't got pregnant this time round. All varying degrees of trivial boll*cks of course. For instance:
- I can get my hair re-coloured. I wouldn't dare dye my hair again if I was pregnant. Not after my freaky skin reaction at 16 weeks pg with DD - a bright red, burning scalp that lasted days, even after I'd washed it about 10 times in freezing cold water.
- I needn't dread delivering at Christmas. That being the due date 'helpfully' calculated by FF (I wish it wouldn't do that) less the number of days that DD was early.
- I can go to my routine dental check up tomorrow and book in for as many x-rays and route canals as may be required. Hmm ...
I was still thinking about the WTF cycle though. I'd put it down to maybe the Evening Primrose Oil, or else the Soy Isoflavones (CD5 - 9), or the DHEA (only 50mg daily, as squeezing in 3 x 25 mg seems quite beyond me).
Then I remembered (doh!) I'd had to increase my thyroid meds (I'm hypothyroid) 6 weeks ago. Maybe this had something to do with it? The whole process of changing the meds was a total saga (drove me nuts) and had meant we couldn't TTC in the month before the WTF cycle (which made the WTF extra infuriating). Fine tuning doses can be a bit of trial and error, and I think too much Thyroxine can mess up your cycles (anovulatory, infrequent AF, scant bleeding etc). So maybe it was that??? Anyway, my repeat thyroid blood tests were due today, so I guess I'll find out when the results come back.
But I think I've found the real culprit. With some trepidation, I went to a private clinic (a scanning service for fertility investigations + early pregnancy) on Tuesday, CD2, to get a new baseline antral follicle count and some blood tests. It seemed like a good idea.
FSH was OK (it was 5 - has usually been about 7 whenever I've checked this past year). Scan of left ovary showed its behaving pretty well for my age (6 antral follicles, given that at this juncture I'm pathetically grateful to have any). Then right ovary, hmm .... The scanning lady said, "if I didn't know differently, I'd say it looks like day 14 for an ovary stimulated by IVF medications ...". This sounded like a good thing until she explained that as well as a few antrals, there were three CYSTS (1 x 3cm and 2 x 2cm). Not 'big C' cysts - although I was in a total panic for a few seconds. But apparently it means I probably didn't ovulate last month (so I've fallen out with FF, which thinks I did) and I might not ovulate again until they've gone. The scan lady said they might well vanish on their own by next month ... but I couldn't help asking Dr Google, who came up with "1 to 3 months" before they'll go. Three months?!!! Plus I'm worried they'll need aspirating or something. I've never had cysts before and right now, I haven't got time for this nonsense!
Anyway, I'm going back for another scan next week (mid cycle) to see what's happening. Sincere apologies for the novella and the me, me, me post. But I am seriously f*ed off.
It'll pass, no doubt.
Hoping everyone else has rather better news! And ...
Fromwest - hope the bleeding continues to subside and the test is negative.
Jass - sounds like your cycle is back to normal, are you trying this time?
Joey - fingers crossed for your 2ww. I conceived DD with a positive OPK on CD16, unusual at the time. Just saying.