hello, thank you for your question on healthcare magic. If your periods have always been regular, this could be a case of pregnancy, even though your hcg level at 5 days post due date of menstruation is not high, this might pick up in another week or two. In some women beta hcg may be low too early on in the pregnancy. I suggest you to get another beta hcg test done in a week s time. If it is negative this time but you still do not get your periods, go for a lower abdomen ultrasound. The second possibility is that, you seem to be having an unusually long menstrual cycle. Since the same hormones that cause symptoms such as dizziness,nausea, bloating, etc during pregnancy also cause similar symptoms during the middle of the menstrual cycle, it is common to mistake it for pregnancy. In both cases, a week wait and then a beta hcg and then an ultrasound can help confirm the diagnosis. Hope this is helpful. Thank you for visiting healthcard magic