Can you have a lower BBT shift and still get pregnant?

My temps before ovulation we slightly elevated above normal due to taking letrozole and getting a flu shot. My bbt only shifted .34 degrees after ovulation. I read that it’s anywhere from .2 or above can confirm ovulation. But I’m worried I might not of ovulated or that the shift wasn’t high enough to be a good ovulation. Anyone get pregnant with only a slight BBT shift?