Ovulation and TTC

My husband and I have been trying for the better part of a year. I had IUD's for 7 1/2 years before having it removed to try to conceive. For the past few years I have had a low sex drive as well. Since having my IUD removed I have been tracking my CM, my cervix and trying to track my ovulation. A few months ago I figured out that Glow's fertile week and my actual ovulation were not the same so I have been trying to track my ovulation from the day after my period ends. I purchased the cheap OPKs from Amazon and for the last couple months I'm not even sure I'm ovulating because the line will start to darken but it doesn't get as dark as the control line and then it starts going back lighter. Does anyone have any advice that might help me out on this journey of TTC? Thanks in advance!