What are the most common symptoms of dysautonomia? Do I need to have all of them to really have it?

Many. Dysautonomia refers to breakdown in the functioning of the autonomic nervous system. Symptoms can include vague but disturbing aches and pains, faintness (or actual fainting spells), fatigue, anxiety attacks, tachycardia, hypotension, poor exercise tolerance, gastrointestinal symptoms such as irritable bowel syndrome, sweating, dizziness, blurred vision, numbness and headaches.