I had sex during my period and one day later i felt dizzy and vomting does it means i m pregnant?

Not that quick: Such symptoms so soon after intercourse are not signs of pregnancy. The process takes a few days for sperm to enter the cervix/uterus/tubes and encounter an egg (if present) .Then it takes a few days for a successful fertilization to create a mass of embryonic cells that could attach to the uterine lining.It is only after successful implantation that you might have pregnancy related symptoms.