Too soon to feel symptoms?

Okay, so, I barely entered my girlfriend earlier this week and she pulled away immediately, but in case there was any chance of her being pregnant,

is it possible for her to feel symptoms 1-3 days after it supposedly happened?

Today she had a headache, which may have been because of cold weather maybe not enough sleep.
She said she was also sleepy, but that may of course be because she didn't get enough sleep.
And she has been in a "ticked off" mood recently, but hasn't lashed out at me or anything.

She said she was in a ticked off mood after I brought up the possibility of pregnancy though, so that may have just been normal.



is it possible for her to feel symptoms that early? 1-3 days?