Thank you for your query.
It is not normal to have such severe cramps and pain after two and a half weeks of the D and C.
You should definitely consult your OB again, and have a check up.
At times, there is some amount of retained tissue inspite of the D and C, and that causes uterine cramping and resultant pain.
Another reason could be a severe pelvic infection
which could cause such crampy pain.
You should immediately get back to your gynecologist for a review check up and a pelvic ultrasound
That will reveal the cause for such severe pain