I am a 34 year old male and have been on singulair for a few days...

I am a 34 year old male and have been on singulair for a few days. It makes me very fatigued and jittery and like others here have stated it feels like I am on a strong stimulant, and I have an elevated heart rate. I am having a terrible time sleeping at night, last night I slept for two hours total. I am recovering from a severe respiratory infection possibly whooping cough so my options are limited, I really need to breath which this medication does let me do, but I can't imagine what a young child must go through with these side effects, just terrible.