Late, crampy, negative

Kris🐶🐶👶🏼
I was supposed to get my af on 7-26. I still havent gotten it. Ive had cramps since last saturday so i definatley thought af was on her way. I did take a pregancy test on thursday or friday and it was negative. 
​Should i be hopeful that i might be pregnant?
​How long should i wait to take another test?