Told i have sinus arrhythmia. told not to worry about it. but others tell me it's dangerous. i'm scared. my doctors won't send me for further tests. ?

Anxiety: Is it sinus tachycardia? If you have no symptoms and pulse rate is not overly elevated - that might be why your doctor wasn't particularly concerned. I see that you suffer from an anxiety disorder. Sometimes heart rate can be elevated with anxiety. Education is often the best source of comfort. See: http://www.mayoclinic.org/diseases-conditions/tachycardia/symptoms-causes/dxc-20253873