Lulu...this is what my RE told me about bbt: she said that it is no longer the gold standard indicator of ovulation and that a lot of factors can play into a bbt spike. She also told me that OPKs are MUCH better indicators of when ovulation is occurring. It is possible that you had a surge and took the test just before the surge (and therefore not detected) or took the test too late after your surge (and also therefore not detected, though much less likely). I'm pretty sure bbt also has to stay elevated for a minimum of three days to confirm ovulation, but again, it's not a gold standard.
For instance, before I was able to start my first IUI cycle, I was waiting for AF to show up. It was really late and I suspected that I might have ovulated on my own (which is remarkable for me) and when I started temping in the mornings, I thought I had confirmed Ovulation because I had 18 days of higher than normal temperatures after having 2 days of normal pre-o temps. I had not, in fact ovulated, and I certainly wasn't pregnant (my lining was WAY too thin for implantation, though I didn't know it at the time).
Some science to also help answer your question: LH (luteinizing hormone - also why the post-O phase of a cycle is referred to as the Luteal phase) surges in order to trigger ovulation. During the follicular phase (pre-o phase of cycle), typically one follicle matures and grows to be anywhere between 18mm and 24mm in diameter. That is known as the dominant follicle and the one that will release the egg. In order for your follicles to mature, estrogen rises, which also helps renew and grow your uterine lining (necessary for healthy implantation and pregnancy until the 2nd trimester when the placenta takes over nutrition and protection - also why pregnancies are more viable after the 12 week point). If you have a digital OPK, the flashy face (CB digitals), has detected a rise in estrogen, which will cue a rise in luteinizing hormone. When you get the solid face, that means the test has detected the LH surge, indicating that you will ovulate within the next 24-36 hours. When your bbt spikes, ovulation has already occurred. Progesterone is responsible for the temp spike and was released from the follicle along with the mature egg. Progesterone is absolutely necessary for a healthy implantation and pregnancy, again, up to the 12th week, when the placenta takes over. You will not have a post-O bbt spike without the extra progesterone in your system. That being said, progesterone can be low, as was in my case during my first IUI cycle, but when I O'd, I still had a temp spike, which was maintained a week later when my doctor put me on progesterone suppositories because my levels were a bit lower than they'd like to see.
OPKs help women to get pregnant because they detect when the body is within 24-36 hours of ovulation. If you BD up to five days before O, but more particularly on the day of O (before you'll see a bbt spike), you have a chance of getting pregnant (20% per cycle in healthy couples). After you've seen a temp spike, it is officially too late to fertilize an egg, because the egg only lives 12-24 hours. Sperm, however, can live up to five days, which is why OPKs are helpful, because they can help couples time things appropriately. The more sperm there are waiting for a healthy egg, the more likely that egg will be fertilized, but the egg won't wait for the sperm. Of course, a fertilized egg doesn't guarantee pregnancy...it'll take another 6-12 days for that egg (now called a blastocyst), to implant in the uterus. If successful implantation does not occur, the woman will get her period and a new cycle will begin.
That's a super long-winded explanation, but I've been doing this for a really long time now and do really know quite a bit more about the female reproductive system than I ever deigned to imagine once upon a time. Please feel free to ask more questions and I'll see if I can answer them for you!
Making a baby really is a scientific experiment. Our bodies aren't all created the same, either, so what's true for one woman (beyond the science I explained above, as that is true for everyone), might not be true for another woman. I'm sorry this cycle is turning out to be so confusing for you and I hope good things come from it!
so i guess that includes lining
ive heard acupuncture can help , might give that a try as i dont think it could hurt 
