The translation "my one and everything" is extremely literal, maybe even to literal. I would translate - "mean everything to me", though i admit that I don't know whether the phrase "one and everything" expresses the same intention.
Hello jairhaas. Thanks for you input. I still believe my translation is ok. If you use "mean everything to me", it would be : "betyder alt for mig".
Well, it's MO so I'll let the expert decide.