What Causes A Pink Fleshy Discharge While Spotting?

I am a female 35 years old. I have been on Seasonal for 3 months and have had some spotting, but now that my period has come, something strange has come with it. A big piece of what I imagine is a piece of my uterus lining has come out. It is about 2" x 3" - but what is bothering me is that it is not very bloody. It is slightly tainted with blood - but quite pink and fleshy looking - should I be alarmed? I am!