What Causes Yellow Fluid Leakage From Penis?

I have a yellowy fluid leaking from my penis. I have had it for 3 weeks and need to place tissues in my trousers and replace then every 2 hours because of persisient leakage and a bad smell.My Dr. gave me Terazosin HLC tablets - to take 1 at night. I think that the leakage has lessened but still persists. The leakage is lesser when I sleep.The Dr. said 2 weeks ago that I should see a specialist. Any comments? I have not had sex so it can t be any STD.