hoping for our rainbow

ok so I know its not totally over til af shows her ugly face , o here is the thing: af is not due till the 4th, I am not really a 100% sure when I ovulated but according to glow it was the 19th, but my other app says the 20th, so I am 11 or 12 dpo, I went to the hospital yesterday after having two vvvvvvvvfp, and they took blood and said it was at 0, is it too early to have a true negative blood test? I think I am out this month😞 I know its not over till af comes. thanks for reading