Very early signs of possible pregnancy

I had sex durning a fertile window last Saturday. But the percentages on glow it says Thursday was the big day. I may be thinking I am just because I really want to! :) so my question how early can signs show? I hardly ever get headaches and I have had them for almost every other day now and I have been peeing a lot more than normal without drinking more or less than my normal.. I took one test and it was negative but I also think I tested to early! TIA ladies