Echogenic structure with vascularity within endometrial canal measuring 2.1x1.8x1.5cm (5weeks after d&c, i was 6 weeks preg). shld i go for repeat d&c?

Possibly: The main concern is that the prior D&C was incomplete, and that there are still "retained products of conception" within your uterus. You should consult with your OB/GYN. They will probably have obtained a blood test for hCG, and depending on the results of that test, the detailed ultrasound findings, and whether you are experiencing bleeding, cramping or other symptoms, you may need another D&C