Ok I think you ovulated on 12-14. Sorry I can't pin it down more than that but it's because you had possibly a bit of a slow rise (this is fine and totally normal, doesn't mean anything, just makes it hard to say 100% for sure) and then also the spotting.
I do want to point out that if you did O CD 14 that was a bit of a cutoff (last BD CD 12) and then the BD CD 15 was too late, so it honestly was not the greatest timed attempt for conception anyway. I mention that only to help alleviate your concerns about your fertility...with less EWCM in the mix, you may have to BD the day before O occurs to have best chances of conception. So please do not worry that this is a fertility thing, I think it's a "we just didn't get the timing quite right this time" thing. :)