Once a decision is made, it cannot be changed.
This seems to be the part of your observation of free will that makes it look logical. The problem is, if the timeline already exists before us, then the decision is already made, and was already made before we existed, and Who is the only One to exist before any of us to make that decision?
Thinking to hard about it is a trap.
I hear this a lot, it is a thought terminator. The only time a person can over-analyze something is when they take into consideration variable which have no effect on the thing they are analyzing. Thinking hard about something is the key to understanding it, just assuming you understand it without thinking about it is the key to being wrong about it and thinking you're right.
Somedays I have doubts about my faith, and everytime I do, I have really bad luck. This concept keeps me thinking though. It blows my mind. Strengthens my faith.
I usually don't like to delve into other people's psychology because many find it offensive and presumptuous, but to me the most likely cause of this is because you "know" that you are doing something wrong by doubting your faith, therefore you "know" that you should be punished, which can result in you noticing bad things more often and possibly even inflicting punishment on yourself via your subconscious purposely making you behave in a self destructive manner without you noticing.
The only things that are truly predetermined by God the Creator are such things as the formation of these beautiful crystals throughout time.
According to chaos theory(or chaos fact as I would call it) if we have free will then this is not necessarily true, because a human could have chosen to do something that would have prevented their formation.
However, this whole idea is quite presumptious of me and may be offending said God so I will ask Him for forgiveness in private.
I'm actually really enjoying this, you seem to be much more "human" than many of the people I have disagreed with on here.