My Period Is 6 Days Late, I Had Sex During

My period is 6 days late, I had sex during my most fertile time it was unprotected at first but my partner didn't ejaculate, I feel nauseous, tired, heartburn, bloated, constipated and dizzy, i have a massive craving for garlic.I took a home pregnancy test on the first day of my missed period and it was negative, is there a chance I may be pregnant