I'm late With a negative test. What do you think?

Marie
Tomorrow on Tuesday will make one week that I'm late for my period, so far test are coming up negative. If my glow calandar is correct then my ovulation day would have been 2 weeks ago from tomorrow which means if I am pregnant I should only be about 2 weeks. 
On top of missing my period, yesterday I was having hot flashes all day and I keep feeling like I'm gonna pike everytime I get stressed out and today I feel bloated and blah. 
What do you all think? Do you think I'm pregnant or something else?