Question: How would a character who is experiencing internal conflict feel?Answer:
The simple answer is that they feel a certain pressure to do things differently or do something they've never done before. They have a sense there is something needed or amiss or that must be accomplished, and they are not certain they can deal with it the same way they have dealt with other problems in the past.
The exact emotion would rather depend on the situation and the character. Some characters might be motivated by guilt or sympathy, others by desire or pride, others by a fear of failure or loss.
Some characters are more inclined to see themselves, their personality or personal failings, as the source of the problem. Others are inclined to believe the fault lies in the world or in other people.
But the essence is the self-doubt - however large or small - in the face of the pressure to change.