Feeling sick;(

I had my Period last Month and I have been trying to Monitor fertile days... I am at my peek yesterday and today!!! but I have been feeling super nauseated in the afternoon for the past 2-3 days?? Could I be pregnant?? Would you even have symptoms like that so soon??? Idk maybe I'm just getting sick;( it's just Weird that only happens in afternoon not All day!  Any Thoughts???