How to know if i have serious symptoms that warrant emergency treatment immediately?

It depends: It is very patient specific. An emergency is certainly something that is causing you significant physical or emotional distress, so that tends to be quite specific to each person. Certain symptoms warrant an emergent evaluation...in the ER, chest pain, significant headache, weakness, passing out, traumatic injury, abdominal pain, short of breath, among other symptoms, are quickly evaluated

EMERGENCY CARE: If you have a primary care provider, you may check there first, but when in doubt, the Emergency Department is available all day, everyday!