IUD HEAVY BLEEDING

I had my copper IUD implanted last week after a medical abortion. My doctor told me I would only have a couple days of heavy bleeding, but I have some serious heavy bleeding! A pad an hour and every time I just even sneeze or pee, a waterfall gushes out.  Im in no pain, but I'm very lightheaded and dizzy. Is this normal? Should I call my doctor? Is my body just getting use to the change? When should I start worrying?