What Causes Delayed Periods Along With Sore Breasts?

I am a day late for my period and have taken 2 tests in the last 4 days which were both negative. I have felt sick for 24 hours with 3 episodes of diarrhoea and have sore boobs. Water and tea also taste vile to me at the moment. Have I just had a 24 bug that is delaying my period or could I still be pregnant?