Hi, I'm 31 And I Haven't Had A Period Since

Hi, I'm 31 and I haven't had a period since the last week of June. My periods are pretty regular every 26-28 days. I took a pregnancy test yesterday and it said negative. I've had period cramps for almost a month now. Every day I say "I bet I start my period tomorrow" because of how intense my period cramps come & go and the lower back pain and upper leg pain hurts bad. I did drink a lot of water before test not knowing it would cause it to read wrong, I have no pregnancy symptoms accept switching moods which I assumed was PMS until it lasted almost the entire month then no period. Other than that Feel awful with period cramps! Is it possible to be pregnant with no symptoms besides what I mentioned and test negative? How long should I wait to test again? Very confused as I've never been pregnant before.