af or IB tmi

Summer
If you have ever experienced anything like this please respond, not sure if I need to go to er or my doctor. 
•Af is due Sunday 5/18/17 , I Stated spotting light brown cm last night 5/25/17
•All day 5/26/17 very "light flow" of brown black blood.....                        
•From 10am to 9pm I only filled a thin panty liner  that looked almost black 
I've been ttc for 5 months & 1 miscarry 12/5/16💔.                                
•What is this? Has anyone experienced this?