Very dark, very early positive...multiples?

Lauren
Hi ladies, 
I am over the moon excited that I got my bfp a couple days ago on Mother's Day.  I did not expect anything to show up since I was only 9 dpo and 6 days out from a missed period.  My line was super dark on this First Response Rapid Results test (which is supposedly not sensitive).  Has anyone heard anything about a strong positive being a sign of multiples?  I just feel like it's odd that I got this kind of result so early!