What I thought was my period lasted for seven days it very light and brown in color have pco but got a normal last month could this be implantation bleeding?

Implantation bleeding typically occurs 10-14 days after ovulation and lasts for 1-2 days. It is usually lighter than a normal period and may be accompanied by mild cramps. While it is possible that what you experienced was implantation bleeding, it is also possible that it was a light period or spotting related to your PCOS. If you are concerned about the nature of your bleeding, it is best to consult with a healthcare provider for further evaluation and testing.