Good Afternoon and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
I am so sorry to hear about sweet Biscuit's condition...I know this is scary especially since she is so tiny!
Most likely she has suffered a digestive disturbance from the shrimp juice that was too rich for her and is not feeling very well. The best thing you can do for your sweet Biscuit is to follow these instructions:
Fast Biscuit for 12-24 hrs to allow the digestive tract to calm down and heal.
Give her Pepcid AC or Famotidine at 0.5 mg per pound every 8 hrs. That can be purchased over the counter at the pharmacy. It will be hard to give her a small dose but do the best that you can.
Give only small amounts of water during the fast or ice cubes
After the fast, feed rice and boiled chicken (2/1)
If the vomiting and other issues have resolved, then wean her back onto regular food. If the they persist especially during the fast, take your sweet gal to your vet for an exam and lab work to determine the cause for this. This is extremely important since this can cause dehydration or other more serious concerns such as an intestinal blockage or Pancreatitis. These tiny chihuahuas are so fragile and their digestive tract is also very fragile. If there is any doubt, take her to your vet.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
Sincerely, ***** *****