When i was 16 a grey curled sack fell out of me and it had a head it had leg and a body that didnt look fully developed. could it of been a clot because i never seen this before during periods and it never happened again?

If you did not have sex before that happened, it was likely a blood clot. If you had sex and had missed a couple of periods, it would be more consistent with a miscarriage.

It sounds more like a miscarriage based on description, if memories accurate. On the other side, if no sexual activity prior to described events, a clot among others remains possible.