What does morning sickness feel like?

I'm not even sure if I am pregnant..I am late, yet got a BFN this afternoon...my urine was very diluted though. Anywya, I feel horrible..my head is pounding, I'm very nauseaus(have thrown up), Im hot or cold, horrible back aches, and chest pain, and I have weird cramps....ugg...I hope Im just not sick. Im also getting veins in my .