I am 49 yrs old and was prescribed Singulair for allergy and asth...

I am 49 yrs old and was prescribed Singulair for allergy and asthma symptoms. I began taking it 2 weeks ago. I find it extremely effective for both asthma and allergy symptoms. Last week I experienced nausea - this has stopped, so it may or may not have been a 24 hr bug. However, I often have a headache and am generally lethargic and starting to feel depressed. After reading the posts here, I realize these symptoms are most likely associated with Singulair so I am planning to discontinue this drug today.