Light bleeding?

I found out on March 3, 2016 I was having a MC. Ended up naturally passing it March 5, 2016 and that's when the heavy bleeding started. I bled for 9 days. Which date do I consider the first day of my cycle?

Note: my husband and I are trying again.

Also , if March 5th ( because of my heavy bleeding ) is my first day. Today would be day 17 of my cycle and I a light flow stared spotting yesterday. Has this happened to anyone else? It's a very small amount. This has never happened to me before. I haven't had mid cycle bleeding before.

Any thoughts? Has anyone else experienced this?