Ovulation test is still positive!!! Is it working correctly?

Me and my husband are triyng to get pregnant again and with our 1st daughter we used the Answer ovulation test and got pregnant on the first month. This time we decided later in the month and bought the test yesterday ( i had my period abut 13 day ago) and i took it yesterday and it said i had the lh surge. and then i took one this morning and it still says there is a surge... i'm confused. i thought the surge was brief? is this test working properly? How long dose a surge actually last and when sould we do our baby dance to get pregnant this month?? thanks!!