What Causes Vomiting Sensation After Eating, Short Periods And Pressure In Stomach?

i lost my virginity a couple weeks ago and i got my period and as i expected it was heavy and stuff but was only heavy the first day and only lasted for four days. and lately whenever i eat something i feel like i wanna puke and when i wake up i wanna puke to but i never do and the idea of food makes me feel sick unless im really hungy and ive been feeling preasure on my stomach above my belly button and im tired all the time and stuff is it possible i could b pregnant?