Anyone notice a difference between a false positive OPK and a true positive OPK?

A couple weeks ago (14 days after getting my iud out) i had what i thought was a positive OPK. I had a second line that was almost as dark as the control line around 10 am, but by 2 pm that line was completely gone and didn’t come back. 2 weeks later i had no BFP or period so i did not ovulate.

Now, i just had a another positive OPK but this time the test line was darker than the control line and i continued to test the next couple of days and the control line actually faded with time. I also had other symptoms like ewcm and pains on left side.

This seems like more likely a true positive than the first. Anyone have experience detecting false vs real LH surges?

P.s. i did successfully conceive baby #1 in 2015 with the help of clomid but trying to do without clomid if possible this time!

Thanks for your insight ladies!!