Thank you for addressing your issue on this platform. I can understand your dilemma and how it must be affecting everything you must have known until now.
While it's true that everything is made up of particles including human beings, you must also remember that human being while also made up of particles, also have so much more to them than just particles. We are considered as social animals for a reason, and it is not just because we can talk, it is because we are capable of so many things that other living beings are not.
The behavior of a person is mostly determined by their upbringing, the kind of company they keep and the kind of situation they have come across and faced. The laws don't really apply here, as it is the circumstances and heredity which shape your behavior.
Before researching on "Free Will", you need to understand what it means. Free will is basically the ability to choose, think and act voluntarily, without anybody or anything influencing your decision in any way. Though many scientists may argue and believe that there is no such concept as that of free will, it is again their choice to believe so. There are also many scientists who do believe in the concept of free will.
I suggest you look for articles online on what free will is and research papers which support the theory. I also suggest that you take up a hobby or an activity which will take your mind off this. Try taking up a physical activity which will let you get rid of the extra energy in your body, as it can also be the reason behind over-thinking.
Do feel free to connect with any of our experts from the platform, if you want to talk about it in greater detail.