Do you think free will exists and is possible, why or why not?

I honestly can't make myself believe it's possible. I have been trying to change my 2 biggest flaws for months. At first, I was able to do it but then it turned into a surprise that i haven't done it in a long time. Then I get historic flashbacks and it always ends up with me falling for the temptation. I don't know what do anymore. I feel like I'm just a machine doing everything on autopilot and anticipate that the outcome will be the same. Any thoughts on this? Do you think we have control of our decisions? - Thanks in advance for answers.