I been on my cycle for about 3 days now , when i went to the bathroom there was a flesh that came out shape like a flower with a long string what is i?

Most likely a clot: If you are having significant amount of bleeding during your period you may get clots that form from the tissue and coagulated blood in your uterus(womb). Unless it is very frequent and your bleeding is severe( for example changing your pads every hour), this should not be a major problem. If it gets worse make sure you get seen by your doctor.