Working while pregnant

I have looking forward to this job and struggled to get it, but in the process i got pregnant. I have not been feeling well and was scared of having nausea at work. Something new happened. On my first day of training i was supposed to work a 8 hour shift. After an hour into working i fainted and puked. I tried to be strong and decided to stay, but i got dizzy again and i had to leave. I dont know if i can go back-im scared to. Should i quit? Or try again?