What Causes Excess Thick Greenish Vaginal Discharge?

Hello, here is my background story to my problem:Since puberty hit me, I have had an unreasonable amount of vaginal discharge. It ranges from white, green, yellow, clear, milky, thick thin, odor and no odor. Id say Ive been having this issues for about 10 years. I keep going to all sorts of doctors explaining my story, and they all keep stating that I have an STI/STD. NO. I do not, because I have been having this issues since I was like 10 before even having sex. Due to the fact that my doctor thinks I have an STI, he refuses to send me to a gyno to get checked out. Now, my discharge has gotten so bad that when it comes out its almost like incontinence. It feels like I am shooting out pee. If I do no wear a panty liner or a tampon daily then it usually goes through and wets my pants. Please tell me what might be causing this issue...