contraception ???????????

[oh-sherbert!]

i had a coil fitted about 6 months ago - since then my periods have been completely erratic. normally they were tip-top, regular and relatively pain free. now there is no pain but they come and go like the number 8 bus! also my boobs have changed - again no pain but i can feel that they are there, not in size but sensation! very strange feeling and a bit worrying - shouldn't my body have adapted to the coil by now?