IUD Spotting

I had an IUD placed this past Monday. My doctor told me to expect spotting for a month to three months, and made it seem like it would be daily. But by Friday I have stopped spotting. Is this normal?! Part of me is worried that something is wrong and I should call my doctor, but I've had other birth controls in the past (the pill- I got pregnant from both kinds that I tried) so I don't know if my body just adjusted to it easier. Any ideas?