Period 9 days late

Hey just a quick question. When did y’all take a pregnancy test ? I’m 9 days late , I took a test Thursday morning(10-3) and it came back negative but I was only 5 days late then . My period has been off about 3 days before but never 9 days . The only symptoms that I’m having is just back pain , tired all the time and some lower stomach pain but nothing like my period cramps . This is my first time experiencing something like this and idk if I’m pregnant or if something else is wrong .