2 days ago we installed new cross drilled and slotted powerslot rotors and hawk HPS pads on my car. The car stops nice but it makes alot of noise from the rear. The drivers side makes a grinding noise when I hit the brakes and the passengers side makes a squeak noise as im driving. Does this mean I did something wrong or do I just need to wait for the break in period to end? Both noises come from the rear breaks. Thanks.