Help a girl out :)

AF is 12 days late which isn't normal as its always regular and on time. I have taken two different hpt and 2 from the same brand came back vvvf positive but negative with the other brand and AF isn't showing signs of coming any time soon. I also think I ovulated late just before my period was due. I have hypothyroidism so I'm not sure if that can even my hcg levels or anything. Does anyone have any advice? And would bloods be the best?