I'm started spotting 5-7 days past ovulation and showing no signs of starting. What could be the cause? Is pregnancy a possibility?

Spotting may = preg. Given the report of 5 days post-ovualtion, the spotting may represent embryo implantation which is associated with spotting. Confirmation would only come from showing a positive HCG in a urine or blood test thereafter.
We never say. Is impossible butbleeding at this point, from a pregnancy this cycle, is not happenning. The implanting blastocyst would be microscopic in size. Intermenstruial bleeding is what you are having, its not unusual but check a pregnancy test of concerned. Good luck.