Has anyone had decidual bleeding?

I'm just asking because I had weird period like bleeding for 2 months and it never turned into a heavy flow to the point where I need to keep changing pads. Bleeding lasted for 5 days I believe since then I didn't have a normal period my last normal one was May 20. Just have a few questions about it and if any of you ladies can answer that would be great. 
1. Does decidual bleeding look like a period?
2. How long does the bleeding last?
3. Can it cause negative HPTs or does the test have to be positive? 
 
Thanks!