Hello lovely, these tests are so stressful. There are people on these threads that are the Oracle on this sort of thing so hopefully they'll post. But I'm going to have a go at telling you what I know, full disclaimer of being ditzy and forgetful totally applies!
Temp spikes come from an increase in progesterone levels which is released by the corpus luteum. If you're not experiencing a spike it could be due to you not ovulating (therefore no corpus luteum). Low progesterone from immature egg. Or, you could be an anomaly as there are a percentage of women who "work perfectly" and don't experience a spike. Opks can help in this case, although they can predict but not confirm ovulation.
You should be getting progesterone levels checked on about day 21ish and lh and fsh levels checked on CD3ish? If they spot a problem they should then do further test depending on findings. Eg ultrasound to check for cysts etc.
If your progesterone is low or your cycles anovulatory, they may suggest something like clomid. However, should they have any concerns about your Fertility you should be referred to a fertility clinic.
The above is based purely on my experiences and as I'm sure you are aware, there are a million different explanations and possible outcomes for you.
It might also be helpful to note that two cycles is not a long time to be charting and all women have anovulatory cycles every so often so the last two might just be down to bad luck?
Anyhow, best of luck and keep us posted. Also, try not to fret, I've been ttc since I was 28, I'm now 33 and have just had 2 perfect cycles without intervention. No bfp just yet but I'm still hopeful 