This episode is looking like gastroenteritis
mostly of viral origin.
Rehydrate her with sips of oral rehydrating solutions and home available, home made oral liquids to prevent dehydration
You can give Tylenol
for fever in prescribed dose and make her in lying posture as she is having dizziness
and blackouts to prevent falls and injuries.
Consult your near by doctor, or General Practitioner for immediate assessment of her and proper management.
Thank you for your query.