As per your description,you have some sort of Gastrointestinal infection.
If your dark brown vomiting is persistent with dizziness,pain abdomen and you are unable to keep liquids down then see a doctor ASAP to rule out gastrointestinal bleeding,Infection.
If you are able to keep liquids down then you can try some self care remedies like
Try OTC Zantac and Mylanta Gas.
Probiotic and citrucel can be helpful.
Eat BRATY(Banana,Rice,Apple sauce,Toast and Yogurt) diet.
Small amounts of clear cold fluids can be helpful initially.
And see your doctor for a clinical exam.
Feel free for further queries.It's good to discuss rather than quit.
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