You are still a Catholic. Your baptismal and conformational marks do not leave your soul. You can come back at any time.
Catholic baptism and confirmation never mark the soul to begin with. That's simply a claim and power grab by a power hungry, control freak, organization which refuses to let go of those who, without any choice of their own, had Catholic baptism inflicted on them.
I am not a Catholic. My old self died. It was crucified in Christ and the live I now live in the body I live by faith in the son of God who loved me and gave Himself for me. Old things are passed away. All things are become new.
Catholics can rail all they want about how *once a Catholic always a Catholic* but that it from the pit. I'm free from bondage now and the RCC has no claim on me at all.
They do not own me. Jesus does.