Im so confused! Whats happening?!

Nicola

My period usualy comes like clockwork. However it is now 2 days late, and i had very light spotting this morning but not even enough to fill a liner. Its totally stopped now but Iv been very nauseas and had alot of cramping. Iv done a pregnancy test every day for about the past 5 days and they are all negative. Whats happening?