Oh this one's funny, rollingmaster! You actually made the meaning the opposite of the original. The last part should be "if you are not with me at my last breath", but I'm not sure about the first part - what does "Neyleyim ben ölümü" really mean? Türkçede açıklayabilirsin istersen.
Neyleyim ben ölümü son nefesimde sen olmadıktan sonra. --> As long as you are not beside me, the taste of death won't be good (Neyleyim --> ne yapayım)
No. As long as the person's darling is with him/her, even death will be something good. That's the meaning of the sentence.
As to "ne yapayım 'bir şeyi'", this phrase means 'it's not good for me/it doesn't work' (it's a rhetorical question). I think the best translation of it should be "what's the good of...". What do you think?