Alignment issue and my word file has been replaced with a pdf conversion.

I'm a Trados newbie and have just tried to align a recent translation in order to improve my TM. I tried to align a pdf and my translation in Word. However, all I now have is the pdf and a conversion of the pdf which has replaced my translated Word file. I can't seem to restore my translation. Firstly, can anyone help me restore my translation? Secondly, what did I do wrong?