Worried

I missed my period for September, completely. I had period symptoms like cramping and tender breast but no period ever came.

So I took two pregnancy tests a week ago, they were both taken like 3 days apart. The results were negative.

Today, there's dark brown blood when I whipped, it wasn't much, but enough for me to notice. And I'm cramping a little.

Things have been stressful but I haven't missed a period because of stress since high school. I'm not really sure what to do or think now.

Should I take another test soon?