Is Delayed Period, Severe Headaches, Cramps And Vomitings Early Pregnancy Signs?

hi, my period was due on 10th of this month. but its running late. just before my due date, i had severe headaches, tiredness and sleepyness. i also had period like cramps, specially near my right side of lower abdomen.but thankfully its over now. i have been vomiting. i did not bleed as i have read that pregnant ladies get spotting. i am desperate to get pregnant.i took a pregnancy test on my 4th day, it came negative, can i still be pregnant?