Ur periods may change date due 2,pressure ur putting yourself in,and lot of stress,sickness,wait 4 like a week or two,than text again. Have a positive mind in yourself girley.
Having unprotected sex can lead to pregnancy so it's always possible. But since you've already since having those symptoms and your period being late and it's came out negative then it's unlikely you're pregnant.
Many things can delay a period, not just pregnancy. Stress, hormone imbalance, illness, STD, cysts etc can all delay a period as well. I would wait another week, and if still no period then take another pregnancy test with first morning urine just to double check.