positive OPK with light bleeding?

[Bookdragon90]

Hello this is my first post here and I was wondering if anybody could offer some help. So me and my partner have only recently just started TTC and I have been off birth control pills for 3 weeks now and I have used a digital OPK and tested today and it was positive so technically today is my first proper day of ovulating but I have been having period like symptoms for a couple of days and I have light bleeding so I don't know if I have started my period? I'm confused as to why it was a positive result if I've started menstruating.

I know if you have enough of either hormones in your urine you will get a positive OPK result, I'm just a bit confused.