Should I Get My Blood Checked Sooner?

I have gone to my OBGYN after a slight bleeding (post menopausal). I am 51 and have had an ovarian cycst removed when I was in my twenties.  After a sonogram, found a 2.6 cycst on my left ovary.  She wants to wait for six weeks and do another sonogram to see if cycst has grown and then do a blood test.  Should I wait that long or should I insist on blood test now.  I am, of course, panicking!