Missed period, Negative Pregnancy Test?

Michelle
I was supposed to get my period on the 26th/27th and it didn't come. On Saturday the 4th I took a test it came out negative.. (It was the 88c one) lol. I'm thinking about waiting til Saturday and buy a better brand lol. This is my second time missing my period and the first time I missed it I wasn't sexually active. I know I saw something on google about stress and caffeine affecting menstrual cycle but idk. This is honestly stressing me out more! On Saturday if my test is still negative I'm waiting until the next Monday and going to the doctor if my period still doesn't show..... Would you guys do that? Or just go to the doctor instantly ?