Decisions or Fate

I am back after a long break. I am sure none was waiting for my blog though my expectations are so. Anyway, I am back and this time it is not any social issue but philosophy. This one is a very short one.
I was talking to my colleague on the way back home and there was a huge argument between us as whether life is destined to be the way it is or whether we have any say in this.
When we make a decision is it that we are destined to take that decision or is it really us making the decision? Is everything decided for us when we were born or does life take twists and turns based on our decisions?
I am of the opinion that my life was already decided and I am just walking along the path we have chosen. But then again I get this doubt. If my life is decided long before why are there this feelings of hate, anger, betrayal, etc. in my life. This also contradicts the theory of rebirth, which is actually caused by our bad deeds in our current life.
So any takers to help me on this question?
Once again I thank you all for your patience. As usual feel free to comment.