did I lose the baby?

Kristen
I'm worried I may have lost the baby or that the pregnancy isn't viable. I want to see if anyone has had similar experiences...
I had a positive pregnancy test at 4w2d... 2 days later I started bleeding. It started as a light pink and brown, then turned bright red. Wasn't enough to fill a pad throughout the day and very distinctly different from a period. 
This morning my bleeding has stopped, bled for 2 days total. Never enough blood to fill a pad, light bleeding only. I called my OBGYN and the nurse said to call on Monday to let her know if I'm still bleeding and to go to the ER if it gets worse. 
I took another pregnancy test this morning and it said "not pregnant." I am hopefully 5 weeks today. Has anyone had a similar experience??