Well, whatever you do, don't tell your doctor that your semen has little or no sperm in it, unless you want to see the doctor laugh. (Sperm is microscopic, unless you put a slide of your semen under a high-powered microscope, you have no way to tell by looking that you don't have sperm.)
Go see your doc or a urologist and ask him why it burns to ejaculate and your semen is yellow. Forget the part about the imagined low sperm count. Good luck.