how long does the lh surge last?

these have been my opks since 10-14 taken everyday in the morning and then one day I did a pm. but the last three were from Friday Saturday and this morning. so I thought Friday morning was pretty positive but I didn't have alot of cm like usual. so today while eating breakfast I could feel alot more cm but my opk don't look as positive as Fridays. I called my doc Friday bc they want me to do a Sims huhner test with my first positive opk but couldn't get me in till Monday at 12:30. what do you think of my opks and today I'm feeling the aches/cramps too that I usually get.