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The tremor is a relatively common side effect to lithium, although it is usually mild. A severe tremor is possible, but much less likely. As your body gets used tot he medicine, the tremor will usually ease off. However, if it is more severe or persistent, the medicine can be stopped and the tremor will resolve.
The other side effects that you mention, such as the vision loss, are uncommon side effects, so are not a reason for concern.
If you do not want to take the medicine because of the possible side effect of tremor, then you would need to contact your doctor tomorrow to discuss an alternative medicine.