The weight of guilt you're carrying shows how much your grandmother meant to you, and that love is real even though you made a choice you're struggling with now. It sounds like you're caught between the immediate relief that gaming might provide and the deeper knowledge that you traded something irreplaceable for something temporary. The hardest part might be that you can't undo it, but you can decide whether to keep carrying this secret alone or find a way to honor your grandmother's memory in other ways moving forward.