LH Surge positive for 8 days?

Ok so I already had a quick question about this at 5 days. However, I am 8 days with a positive LH surge. I took a pregnancy test and it was neg, then looked at PCOS and I don't have that. Started testing my urine in the middle of the day instead of FMU. What could cause 8 days of LH surge?? Technically I am suppose to start my period Feb 10, 2010. Any ideas?