OPK questions?

So I am trying to figure this out it's my first time using opks.

I got my postive opk this morning at around 11am

I have ewcm to go with it and twinge pains here and there.

Now I tested again around 6 pm today and its negative?

I did hold my urine for 2 hours I would say. I thought surges were suppose to last longer?

So if my opk is no longer postive, does that mean I am currently ovulating as we speak? I am worried because my husband wont be home for another hour and I got my postive opk this morning. Worried I will miss it