I've only been taking Singulair for about a week, but the headach...

I've only been taking Singulair for about a week, but the headache started shortly after I began taking it. It's a nasty sharp throbbing across my right temple. My ears have been pretty much constantly plugged and I can feel pressure in my sinus cavity. I went on double doses of zytec and zantac in order to get rid of sinus pressure (headaches, ear aches, and face pain) in the first place...and now it's back. I can breath better, but my asthema wasn't that bad to begin with. For me, the side effects aren't worth it.