Had miscarriage and dnc 3 weeks ago lots of clear watery discharge. when i went to 2 week doctor said it was ok could been from dnc but still have dc?

Depends....: Well, depends on amount, odor, any blood or change in color and other things. Should be decreasing, but if not, or increasing, your doctor should know!

Discharge post D&C: It is not uncommon to have discharge after a miscarriage and D&C for up to a month. As long as you don't have fever or pelvic pain, I would wait. This problem is usually self-limiting, and should resolve itself without treatment.