1) Aging 2) Causing anxiety 3) Disagreeable 4) Full of tension 5) Hard to bear 6) Nerve-racking 7) Nerve-wracking 8) Trying 9) Very hard on the nerves 1) Disagreeable 2) Disturbing 3) Tense 4) Upsetting 
• (a.) Having much stress.
Stress'ful adjective Having much stress. Rush. 
stressful 1. Causing or involving mental or physical stress or strain. 2. Full of stress or tension. 3. Any physical, chemical, or biological condition that can induce stress, strain, or distress.
full of stress or tension: the stressful days before a war.