I am experiencing 75% of all of the "less frequently" reported symptoms including in ability to sleep, agitation, diarhea, muscle pain, restlessness, palpitations, upper respiratory problems, major joint pain. I'm terriefied that I have a few of the report to your doctor right away symptoms which include a flu like illness ( I couldn't figure out why it felt like I kept coming down with the flu for six weeks) swelling of my sinuses and pins and needles in my feet and numbness in my arms. I will never, ever take this drug again! It's 1:20 AM and I feel like I should go to the ER after realizing that what I'm feeling is due to singulair, but I'm trying to hold off and just see my doctor in the morning.