Period at the beginning & end of a month?!?

Ok, My period has been soooooo irregular all my life, & now it starting to straighten up! My problem is, I had my period at the beginning of this month, & now I have it again! I don't really know if that is normal or not. I went for a blood test the other day to see if im diabetic (which is a whole nother story) but anyways, if I had cervial or ovarian cancer, do you think the blood test would have detected it? The doctor said everything seemed fine! But, is it normal or could it just be my period straightening up? & No, im not pregnant!