General synonyms:
* Inner turmoil
* Mental struggle
* Psychological conflict
* Inner conflict
* Self-conflict
* Moral dilemma
* Agitation
* Unease
* Disquiet
* Angst
More specific synonyms:
* Ambivalence: Hesitation between two opposing courses of action.
* Doubt: Uncertainty or lack of confidence.
* Guilt: A feeling of responsibility for a wrongdoing.
* Shame: A feeling of humiliation or distress caused by one's own actions.
* Fear: An unpleasant emotion caused by the anticipation of danger.
* Anxiety: A feeling of worry, nervousness, or unease.
* Stress: A state of mental or emotional strain or tension.
* Cognitive dissonance: Mental discomfort experienced when holding two or more conflicting beliefs, ideas, or values.
The best synonym will depend on the specific context.