Need a bit of advice on conception and sings please?

hi i had my last period on the 5th of june, the 14th 15th and 16th i had unprotected sex with my partner, ever since i have had little pinching heated sensations in my lower abdomen, it also feels like something is being tightened up inside and when this happens i feel little butterflies in there. i have also tried going to the toilet through the back but it seems to be pushing my womb and kind of hurts, but i have never felt this sensation before, i also feel rather sick when i get these butterflies. could i be pregnant? as i have been reading up online and some people have been having symptoms of pregnancy 1-2 days after sexual intercourse, any advice will really help thank you very much x