OPK help!?

Ok so last period was 1st-4th and then got positive OPK on the 9th. AF was due 4 days ago, no signs of her coming. These are over the last three days. I am 5 months PP but we've been ttc since 5 weeks pp and I've had regular periods for 2 months now. Any suggestions ladies ? I dokt know why I am having another surge without a period