Bleeding at 5 weeks!

Monday morning I noticed blood when I wiped and throughout the day it got a little heavier, not as much as a period, but I wore a pad all day and it was halfway full at the end of the day and the same thing Tuesday, about a half full pad all day. Today (Wednesday) I just have spotting and have not even came close to filling a pad. I've had no cramps but a dull backache the past 2 days. I called the doctor's office and the nurse told me it's basically a "wait and see what happens" deal and if I felt uncomfortable to go to the ER. Since the bleeding has almost stopped I did not go to the ER but have an appointment tomorrow at the doctor's office. Anyone have this happen to them? If so, what was the diagnosis?