Examples of serious problems include new onset seizures, weakness on one side of your body, unusual significant headache, fever when your blood counts are low, worsening shortness of breath, inability to hold down liquids or solids leading to dehydration, chest pain that could be a heart attack, etc. This is only a partial list. Regardless of what you are told by family, friends, or health care providers, if you are having a serious problem do not “wait it out” at home. The emergency room is the best and only place that can perform a rapid assessment including laboratory and imaging tests.