Over the past year and a half I have been having issues with my menstration. Some months I miss it, and other it comes. The last six months have been the most difficult. From August to November of 2009 I didn't have a period.( I took a home pregnancy test and got a blood test both were negative.) In December I had a light period, which is unusual for me, and it lasted about 9 days. In January of 2010 I bled, some days heavily and some not, through out the entire month. And thus far in February 2010 I have not had one. My question is, Should I be very concerned?