What Causes Stringy Vaginal Discharge And Back Pain?

right well i started my period on the 20th of i then had unprotected sex on the 6th day period stopped i then began to bleed a bit the next day but it was brownish and very light..

now today is the 12th of september for the past week i have been feeling very tired.. no energy my whole body just feels like its aching constantly .. and im experiencing really bad back pains ,headaches and cramps in my tummy area.. im having really bad discharge aswell like to the point when i urinate it literally falls out of me sometimes in lumps and its very stringy..also im very skinny size 6 and always had a flat tummy all of a suden its just really bloated especialyaround my uterus area its just soo swollen.. ive taken a test today but it came back negative could this be wrong..and would it be to early to no if im pregnant?

someone please help me!!! im just so confused