Do we know what Jig is thinking in the story "Hills like White Elephants"?

This story is all about communication and how people do it and how effective it is or isn't. To infer what Jig is thinking in the story, readers need to examine not only what she says out loud, but also how she behaves and the effect her words, actions, and tones have on the American.

One of the first comments Jig makes that stands out is this:

"They look like white elephants," she said. 
"I've never seen one," the man drank his beer. 
"No, you wouldn't have." 

Though this seems at first to be a slight insult about how the American is not as well-traveled as she is, this comment also begins to show Jig's disappointment at the man. As the story continues, readers discover that this disappointment comes from her not wanting to have the abortion that the American thinks she should get:

"‘It’s really an awfully simple operation, Jig,’ the man said. ‘It’s not really an operation at all.’
The girl looked at the ground the table legs rested on.
‘I know you wouldn’t mind it, Jig. It’s really not anything. It’s just to let the air in.’
The girl did not say anything.
‘I’ll go with you and I’ll stay with you all the time. They just let the air in and then it’s all perfectly natural.’
‘Then what will we do afterwards?’
‘We’ll be fine afterwards. Just like we were before.’
‘What makes you think so?’
‘That’s the only thing that bothers us. It’s the only thing that’s made us unhappy.’
The girl looked at the bead curtain, put her hand out and took hold of two of the strings of beads."

Jig's silences are speaking for her loud and clear here. She does not want to get an abortion and she does not want the man to ask her to. She wants to escape the conversation, looking at the curtain and the table and anywhere but the man's face. Also clear here is Jig's realization that their way of life has been lost by this pregnancy and, whatever choice they make, they will never be how they were before. She mourns this and is also frustrated that the man does not acknowledge it. 

Later on in the conversation, it seems that the man has convinced Jig to have the abortion. She says,

" 'Then I'll do it. Because I don't care about me.' "

Of course, she is not just giving in to the man's persuasion; she is also letting him know in no uncertain terms that by agreeing to this abortion, she would be putting his comfort above her own self. Naturally, he recoils from this and they continue to argue about it.

At the end of the story, Jig's final words are ambiguous:

"'Do you feel better?' he asked. 
"I feel fine," she said. 'There's nothing wrong with me. I feel fine.'"

This could be interpreted a few different ways. Perhaps she means that she has resolved herself to the idea of getting an abortion and is now willing to go through with it. Perhaps she is insisting that her pregnancy is not a problem and she is "fine" despite it, because she will keep the baby. Perhaps she is only considering this current moment and declaring herself "fine" just for the present, to enjoy one final afternoon before everything changes between her and the American. Jig's communication here seems purposefully vague.