Guaifenex and tiger

I took this drug for 2 days, and then stopped due to sleeplessness, agitaiton, and extreme congestion even when I took it with the water, like the script said!! I am never taking this again, and will throw away the rest of my full bottle, so I don't make the same mistake twice!
I tried to go back to work today after a 5 day abscence due to my previous flu, and then had to go home again just for the side effects of this medicine. I couldn't function and even think straight. I felt just like a tiger pacing in it's cage all day.....
And I have never in my life felt so out of control and agitated, even drivng a car was bad!
In short, I will try other remedies for my congestion.....