Food Poisoning (Viral or Bacterial): This is the most likely diagnosis due to the direct correlation between ingesting shrimp and the onset of severe vomiting. Shrimp can be contaminated with various pathogens such as Vibrio vulnificus, Salmonella, or norovirus, leading to food poisoning.

Allergic Reaction: An allergic reaction to shrimp is a common condition that can cause severe vomiting among other symptoms like hives, itching, and difficulty breathing. The severity of the reaction can vary widely.
Scombroid Poisoning: This condition occurs when fish (including shrimp) that have high levels of histamine are consumed. Symptoms can include severe vomiting, diarrhea, and abdominal cramps, often resembling an allergic reaction.
Gastroenteritis: Viral or bacterial gastroenteritis can be contracted through contaminated food or water, and shrimp could be the vehicle if it's contaminated, leading to symptoms like severe vomiting, diarrhea, and abdominal pain.

Anaphylaxis: Although less common, anaphylaxis is a severe, life-threatening allergic reaction that requires immediate medical attention. Symptoms can include severe vomiting, difficulty breathing, rapid heartbeat, and a fall in blood pressure.
Botulism: While rare, botulism is a serious illness caused by a toxin produced by the bacteria Clostridium botulinum. It can be contracted through improperly preserved or contaminated food, including seafood like shrimp. Symptoms include difficulty swallowing, slurred speech, and muscle weakness, which can progress to paralysis.
Vibrio Vulnificus Infection: This bacterium is found in seafood, particularly in raw or undercooked oysters and possibly in other seafood like shrimp. It can cause severe illness, especially in people with weakened immune systems, and can lead to septicemia, which is life-threatening.

Ciguatera Fish Poisoning: This rare condition occurs from eating fish contaminated with ciguatoxins. While more commonly associated with larger fish, it's a possibility if the shrimp have ingested contaminated smaller fish or algae.
Paralytic Shellfish Poisoning (PSP): Caused by toxins from certain types of algae that can accumulate in shellfish, PSP is rare but can cause severe neurological symptoms, including paralysis, and can be life-threatening.
Tetrodotoxin Poisoning: Found in certain marine species, tetrodotoxin is a potent neurotoxin that can cause paralysis and death. It's extremely rare in shrimp but could be considered in cases of severe neurological symptoms following ingestion.