Thanks for all the responses.
I followed Greg's advise, called up my new employer and was re-offered the position.
Why did I turn down the offer in the first place?
Failure to take into consideration, during my deliberations, the fundamental reason why I wanted to move on in the first place, coupled with the fact that my present employer decided to match the terms of the new offer. Also, I did not give myself enough time to thorougly think things through. One more lesson learnt.
In response to SMS' suggestion, I could not sit back and wait for a counter offer. This opportunity had already been missed when I initially declined the offer. Even though my decision making capabilities have been compromised in the eyes of my new employer, I am taking my chances to rebuild their confidence in me.
On the bright side, my control system is still very responsive, as it did not take me long to correct the error resulting from heading towards the wrong direction.