Hello I am Dr. Joey. Thanks for trusting me to help you and your pet today. I am a licensed veterinarian with over 15 years of experience. I look forward to working with you.
This is concerning, given how small Lucy is and how much was ingested. This has potential to cause toxicity, if she ate the whole thing. My calculation is she ingested a dose of 138 mg/kg. I must recommend you proceed to your closest veterinary ER now for her to receive support and potentially get her to vomit this back up.
Toxicity with large dosages like this can cause symptoms such as include drowsiness, weakness, low heart rate, low blood pressure, low calcium levels, respiratory depression and heart arrhythmias.
If the ER vet can get her to vomit this up and the administer something to try to absorb the rest (activated charcoal) that might be very helpful. She also would need her lab work checked to see what her magnesium level is as well as calcium.
Because she is so small it is much better to err on the side of caution and have her examined on emergency rather than wait for her to show symptoms.
Please let me know what questions you have.