5 days late, brown blood??

I'm never late and ever since my first LO my periods have been insane with pain and always on time. We'll I feel slightly crampy, and been nasous for a few weeks prior, and yesterday started what I thought was af, but is only a dark brown color? Still the same today. I can't be pregnant, seems we barely find time to be intimate...I havnt taken any tests yet, bc I didn't know I was late till yesterday when I started spotting...gonna take a test in the am...

What do u all think?