General Synonyms:
* Depressed
* Dejected
* Disheartened
* Downcast
* Hopeless
* Pessimistic
* Dispirited
* Low-spirited
Synonyms emphasizing a lack of confidence:
* Doubtful
* Uncertain
* Hesitant
* Apprehensive
Synonyms emphasizing a lack of motivation:
* Uninspired
* Apathetic
* Indifferent
Synonyms emphasizing a feeling of being overwhelmed:
* Overwhelmed
* Overburdened
* Weary
* Exhausted
The best synonym to use will depend on the specific context and the emotions you want to express.