Missed Period With Light Brown Creamy Discharge, Negative HPT. What Is The Cause?

Hi my names Monique. I have a query regarding my menstrual cycle. For the last 8 years I have had no need for concern however in the last 3 or 4 months it s been difficult for me to keep track of the exact dates that I should be menstruating but from what i can gather they have been up to a week late..but this month i havent had a period at all...i think i was due on the 29th of June and it never came. Obviously i have taken a HPT , that came back negative about a week ago and then last tuesday i began having a light almost creamy brown discharge , no different to the discharge i normally get at the beginning of my period however the bleeding never started but the discharge did stop almost 2 days ago now. I took another HPT on saturday afternoon which also returned negative...im starting to worry. Please help!