Hi, I lost my original source code that is loaded on my Mega2560. Is there any way I can read it and retreave it from my board?
You can read the binary data using the avrdude program that comes with Arduino. Unfortunately that won't get you anywhere near the original source code. You would need to translate the binary machine code to assembler code and manually convert the assembler code to C++ code.
It may be easier to re-create your sketch from scratch.