help!! scared at the doctors!!

So I've had a discharge since before my period even started (3 yrs ago) and I went to the gyno for birth control but was to scared to bring it up... Some days it's really heavy and clear/ snotty consistency and other days it's like cottage cheese and not a lot... If I put a tampon and take it out when it's time it almost looks like there's a greenish snot on some parts of it?? Some days it smells and some days it doesn't... WHATS GOING ON!!