What Is The Irregular Brown Stringy Discharge With Trace Of Blood?

I have been having a brown stringy discharge for about 4 weeks now (since about a week after my last period). It is more than my normal amount of discharge, and I have to wear a panty liner. Also, the discharge is odorless. Sometimes there is some blood that is a very light red color. Last month my period was six days early and it has been 36 days since the beginning of my last period. Usually my periods are 30 days apart. I am not experiencing any discomfort or other symptoms. It isn't possible that I am pregnant or have an STD. Should I be concerned? I'm starting to get a little scared...