very early pregnancy symptoms. help please

How soon did you experience pregnancy symptoms? 
I'm on the pill and about 2-3 days after I had sex  I experience nausea, cramping and frequent urinination. Is this too early for symptoms? 
I had sex on the last day of my period (period had finished) I don't think I ovulate because I'm on the pill. 
*took a tests-it was negative and been getting my period* *This happened a few months ago*