Trigger waning bleeding during pregnancy..

Ok so I am only 5 weeks and 5 days. Today I noticed some brown ting to my CM. This lasted a few hours and seems only to be mixed in with the cm. I called my Doctor and they can't get me in til Friday. Advised me to go to the ER if it picks up etc... However my test it getting darker everyday! Should I be concerned? The spotting has stopped..