I had a positive opk on 28th august .at 1:30pm. We had sex the night before and Thursday before . Then the Wednesday after . I have done a 20 mil preg test today and yesterday. Both negative . My last cycle was 38 days long. So I know I am not late yet . If I ovulated on 28th surely I should have my period by now? The positive opk is below. Was it truly positive ?