1st Trimester spotting??

Woke up this morning, went to the restroom, and discovered some old brown colored blood when I wiped (sorry-tmi I know). According to my dr, I'm almost 6 weeks along...I called and spoke with my dr and her nurse, and they are reassuring me this is normal and can happen, and that it doesn't mean anything is wrong...that it could have been caused by intercourse. I'm trying to relax and not worry, but this has me pretty shaken. Has anyone else experienced this ??