Can Levosiz Cause Dizziness, Cold Palms And Drowsiness?

I took one tablet of Levosiz 5mg post dinner because I had dust allergy, and the next morning, I could not stand properly soon after I woke up from bed. I had cold palms and feet and felt very light headed and sleepy. My eyes were blacking out as well. Could this be due to some side effect of Levosiz?