How to practice acceptance and gratitude if fw is illusion?

Hey,

I have chronic pain I keep reading (even for other issues) to practice acceptance, or gratitude. But free will is most certainly illusion, even we can't technically prove it yet! Concept of gratitude is absurd to me, I should be grateful for suffering and being raped? Like WTF? I didn't ask for life... It is just so stupid and absurd... I know my brain creates my reality. But I Am very rational, I can't lie to myself, I always tell myself truth how it is... I know believing that you are smarter than you are, or that you have good memory can really improve it! Or that you have more control that you have, but again I can't absolutely lie to myself. It frustrates me I can't use these tools. It is probably impossible for me, because I have love for truth and I Am extremely rational and say how it is and can't lie to myself, but worth asking!

PS: I don't want to argue about fw, "Man can do what he wants, but he cannot will what he wants" - Einstein

Thanks!