On my trading performance

For the past few months, I have been able to achieve an average of 0.6% trading gain of my account value on the weekly basis. The problem is that had I always followed my trading calls, I could have had a 2% weekly gain, if not a lot more. The reason? I am having difficulties to overcome the "fear factor": I often failed to pull the trigger when a pre-planned setup arrived because of the unwillingness to accept the calculated risk, what's even worse is that I almost always exited my winning positions prematurely because of the fear of losing profits (often only obtain 20% or less of a favorable run). I know that I will never become a true winner until I can overcome this psychological hurdle, and I am struggling to find a solution. This is getting really frustrating for me!