Ovulation tests vary so much! Are they still reliable?

Dear ladies,

I'm really curious about your experiences regarding the following:

I regularly use ovulation tests because I have a very irregular (long) cycle and, due to a miscarriage, I've lost my right fallopian tube. As a result, my chances of conceiving have decreased significantly, so my gynecologist advised me to use ovulation tests to track my ovulation. Yesterday, I got a negative result from the Kruidvat test (the second line was about 70% as dark as the control line), and this morning, I suddenly got a strong positive. I was a bit startled by that, was about to head to work, and upon returning, I took another test. This time, the second line was very faint. So, basically negative. Just to be sure, I did an Etos test afterward, and that was completely negative. Could I have ovulated anyway? Or was this likely a false positive?

Hello, because otherwise I'll have to call my boyfriend so we don't miss this opportunity We've already had so few chances.....

Thanks for any responses; I appreciate it in advance....