I was once toxic. I had diarrhea, vomiting, large muscle tremors, loss of cognitive function (couldn't look up a number in the phone book b/c I didn't know the alphabet; when doctor asked my DOB I didn't know it), inability to walk unassisted.

Your symptoms don't sound toxic... here are symptoms from a website:

ACUTE TOXICITY
After taking too much lithium you will have symptoms such as:

• Diarrhea
• Dizziness
• Nausea
• Stomach pains
• Vomiting
• Weakness

You may also have some of the following nervous system symptoms, depending on how much lithium you took:

• Coma
• Hand tremors
• Incoordination of arms and legs (ataxia)
• Muscle twitches
• Seizures
• Slurred speech
• Uncontrollable eye movement (nystagmus)