I don't think there is any need to go to ER as you had just few vomiting and diarrhea.
It seems to be a viral gastroenteritis
Take care of your hydration and keep taking plenty of oral fluids like water,juices,coconut water etc.
You may take some anti vomiting medicine like domperidone
10 mg twice a day for a day or two.
You should settle in couple of days
If fever is high or having lot of body ache
,you may take some paracetamol
,whenever required but should not be more than 3 to 4 times a day.
Best of luck