Late period

I am exactly a 28 day cycling and with a 6 day period. I was due for a period on 4th of July, it has not come yet making me 7 days late. I took a test last night it was negative. I am not sure if I should cry because I'm not pregnant or wait and take another one. There is no sign of a period coming, no spotting nothing. I know my body and this is not something that ever happens. Please is there hope.