Anyone with a blood clot & on warfarin developed another clot?? ?

I'm on warfarin as I have a clot in my lungs & my ir is ok but just want to know if anyone has developed another clot as I've been gettin breathless but doc says its normal as its scarrin on my lungs but nurse says go to a&e,I'm always bein told to panic one min but the nxt just relax,any advice would b great