Let me help a bit.. It depends on the original word.... If she say "dekinai", that means "I can't do it"There are a lot of weird phrases in this machine translations. Sometimes even funny. In this particular case, I would translate it with "I can't take it anymore". (so comfortable - "feel's so good", for example). But I think a lot of people can make better suggestions.
If she say "gaman dekinai", that means "I can't hold/endure it"
If she say "mou gaman dekinai" , that means "I can't hold it anymore"
Hope this helps..