What Causes Spotting, Tender Breasts, Cramping And Nausea?

I'm Confused. Every month my period is like Clockwork w/ 33 days in between. I'm married n we don't use any type of Birth Control. My period was due 9/27. On 9/22, I spotted for about 2hours- Nothing made it to my Liner. Today(9/29), It happened again. It was a little more and darker instead of l. pink, but still never made it to my Liner. Only lasted a couple hours and now its Gone... My Breast are Tender, Slight Cramping, and Nausea a couple hours one day. I lost a baby girl at 19 weeks so, I'm nervous. Please help me and Thanks so much.