I thought my allergies were acting up so I took loratadine. As the day progressed I got extremely drowsy, my body started to ache, and I had a horrible sinus headache. My throat swelled up where I was wheezing horribly. I finally came to the conclusion that it could not just be allergies, but it had to be a cold since it was getting progressively worse. This morning I woke up with another headache and now my snot is green. I am positive it is a sinus cold now. The allergy medicine did nothing, but only seemed to make me really light headed. Does allergy medicine, if taken when you don't really have allergies, but in fact a cold actually make it worse or just cause side effects like drowsiness?