Length of lh surge

How long does the lh surge last?  I had faint positive lines on mon, tues and Wednesday (days 8, 9, and 10).  Wednesday afternoon (I test 2x per day) it was strong positive.  Today both am and on are strong positive.  Hubby and I had sex last night.  And we are going to again tonight.  Should we do tomorrow too...if the opk is still positive?