Since you've taken 2 tests and a blood test since your period has been late and they've all been negative then you're not pregnant - if so it would have shown in the blood test for sure.
Many things can delay a period (even if it's never been late before) - stress, illness (which would explain the vomiting), infection, STD, hormone imbalance.
I would wait another week and if still no period then go and see your doctor. if you don't stop being sick then I would go before then and see if there's something they can do for that.
please help... i have never missed my period before