Positive OPK for days????

I tested on the 31st with a very close positive. So I tested again on the 1st and got a positive but on the 2nd and now the 3rd its still the same shade of darkness as it was on the first. I am 99% sure it's a positive too. Has it happened to anyone else? Is it just my LH surge from the 1st???

I had 3 days of strong positives the cycle I conceived my son. Good luck!

When we conceived this one, mine were positive for 3-4 days.

So it's normal to have it positfve for a few days then? I only had positives before for like 2 days lol