Symptoms at 6dpo? Really?

I have just entered feeling nauseous into my fertility friend app and whilst checking the pregnancy monitoring analysis it said that was a top sign at 8.6% does this mean it's possible but rare? my temp dipped today, I've read it could be from implantation. Will have to see what happens with temp tomorrow.

What are your thoughts on having symptoms this early? Has anyone had symptoms this early? Fertility friend has told me to test on the 20th..seems so far away! But don't want to test too early and be disappointed