Pregnant ??

Hey all! I’m officially past my period dates. I normally always start around the 20th of every month.. my cycle usually lasts about 6-7 days. Yesterday I was supposed to be off my period but I’ve never started. I took a pregnancy test and it came back negative. Today is the 27th and I’ve never started yet. Is it too early to tell on a test?? Should I take another one in a week?