What's the difference between period and implatation bleeding ?

It's almost never: Implantation bleeding, that is largely an internet myth. If - a big if - you actually get implantation bleed it woudl be about 6-7 days after ovulation, or about a week before your expected period.

Amount : A period usually occurs at a normal time and lasts anywhere from 5 to 7 days. Implantation bleeding can vary in onset but usually last for a very short time and it is not very heavy.