Muco-Fen and expectorant

I took last night and felt dizzy, highly agitated and anxious. Needless to say I did not take it again. I am a little confused because I have taken an over the counter liquid expectorant with a cough suppressant many times and never had this type of reaction. I felt I should have had some type of warning about this. Luckily for me, I was at home on the couch instead of having to function at work or even worse, driving somewhere! It's horrible and I will never take it again!