Positive OPK for 3 days in a row?

My LH surge usually last 1-2 days. Today I tested and my OPK was positive for a 3rd day in a row (not on any medication, not using digital tests). Has anyone experienced this before? ... I'm also feeling more ovulation symptoms than usual (tops and sides of breasts are tender, dull cramping). I'm on CD 19. Why would this happen?