Ovulation

Hi everyone. I have had two eptopic pregnancies. The first was treated with methotrexate and the second ruptured and the tube was removed. That was last march. My husband and I have "tried" since with no luck. This month I used OPK's for the first time and had posative results on CD 15 and 16.  Then negative until CD 22. Now at CD 27 still pos OPK but neg HPT's. Any thoughts? Appreciate any advice! Thank you so much and good luck to everyone! Xo