Spotting

Hey Ladies quick question has anyone else experienced "spotting" during their first trimester? I woke up Friday went to the bathroom and when I wiped there was in my opinion significant red blood when I wiped. I went to the ER to get checked out with the doctor there doing a physical exam, ultrasound, bloodwork, and urinalysis. They said everything appeared normal and no sign of a source of bleeding but I am still very scared. The bleeding has stopped as if it never happened. Has anyone had a similar experience?