Brown old blood clot

Ashley • 34 years old & married. Have a 2.5 old DD. She was a preemie. Not trying to prevent but not actively trying for now. If it happens, it happens.
I know this is gonna be TMI, but need advice. I am currently 6w6d. Thursday night (11/13) I went to my local er due to bright red blood bleeding on my tp when I wiped. They did a urine sample, blood test (beta HcG), u/s, and pelvic exam. Everything came up fine. I went home and told to rest. I have had some brown discharge which I am assuming is old blood. I am being told by select friends that know that is a positive sign. This morning in my masters class, I went to the bathroom and passed a brown old blood clot. It was about the size of a nickel. Is this normal? Should I be worried?