possible to still have old miscarriage tissue

i am a little scared.... early last year i had a misscarriage at 7 weeks.i had not been for d&c assuming everything would come out naturally, and it did (again assuming) as i bled and had severe cramping.
i am now 5 months pregnant again and have no issues such as spotting or cramping.
this mornng when i went to pee, something came out of me, it looked like old amniotic sac.it was about 5cm,very brown in color (similar to that of old piece of chewed meat) it had what looked like sinew on it aswell.it wasnt sore when i passed it, and i havent bled or had any cramping.

i was wondering if perhaps it could have been from an old menstral cycle, or old gestational sac or an old piece of uterus or something...
im worried that perhaps it could mean that i am about to have a miscarriage.

please could anyone tel me if theyve had similar expiriences,should i be worried???

[Omacastrop]

Please call your doctor. You just can't take any chances with your health, or the baby's.