Is it time to let myself out of the mental "jail" I put myself in when Ebony died?

I blamed myself all these years, sometimes I still do blame myself for not stopping the cancers, I still get upset and flashbacky over her last ngiht with me, when she couldn't walk in a straight line and kept walking in circles and having fits, I got her to the vet as soon as I could but it wasn't enough to save her, cause she had brain cancers as well as asthma and cancers in multiple parts of her body and she had things wrong from when she'd been rescued that were just about under control

Inability to forgive myself over everything Ebony went through, caused me to put myself in the mental jail, I still don't know to this day if I can let myself out of it, or even if I deserve to let myself out of it