First off, I want to thank you guys for your responses but I think I need to clarify my situation.
I want to point out that I had a functioning circuit (i.e. my motors turned as I wanted, althought I couldn't get the code to balance it), hence this is not a problem with my circiut. However I had to shelve my project twice wherein I disassembled the robot to store it safely and after reassembling it, the chip was broken.
As for the wrong circuit, I just slapped together the circiut for the purpose of illustration and didn't see the mistake. Sorry 
. As seen in the image, the chip is definitely dead (and wouldn't work even on the correct circiut).
I want to know what is the cause of the chip getting bloated the way it did and how to avoid it.
