Maybe get it checked out to put your mind at ease. I am hoping its nothing.
Dont worry I ovulate 3-4 days after a positive OPK too and about 20/21cd.
I have decided that if we are unsuccessful after our March cycle that I will go to my FS asking to do IUI.
We will have been trying for over 1.5 years and the unexplained infertility crap is just not going to cut it.
If she is unwilling to do that I may look at getting referred to a new FS or ask for more aggressive testing as we have only done the basics.