Concerned!! Need advice?

I am 14 weeks pregnant and two weeks ago i started spotting and bleeding and went to the er twice and my doctor and found out i had placenta previa or a marginal one and it was causing my bleeding and they said the baby was great. Well today i am spotting some again but instead of being blood red like before it is a really dark brown now and it didnt start till the next morning after i had with my boyfriend. I was wondering if any one else has had this marginal previa and if its normal to spot after especially this dark brown color also i dont have any pain or cramping.