I am 30 years old and have suffered with severe allergies all my life. My allergy doctor suggested Singulair in Sept. 03 and I have been taking it ever since. A couple of months later I had my first panic attack and have suffered from these ever since. I also suffer from frequent headaches, stomach pain, dizziness, tingling feelings in my arms and feet and leg pain. I am anxious all the time constantly worrying about things and paranoid. I have been to numerous doctors and had many tests run and they can never find anything. Before taking this medication I had never experienced any of these feelings. I feel like I have lost 5 years of my life and and wasted a lot of money. I wish I had known about these side effects. I am stopping this medication immediately and only hope these feeling will subside.