Pseudoephidrine symptoms and conditions

I have severe allergies. They are so bad, my ears hurt and I have massive headaches. I thought I had sinus problems as well. My new doctor said it wasn't sinus problems, but my allergies got worse. She put me on Singulair. It took a week for it to get in my system. It "worked" for about three. But I noticed I had an excessive amount of mucus. I was a mucus making factory. I was not sleeping through the night. I kept getting up, coughing, and spitting up clear, thin mucus. It was horrible. I started taking Mucinex and Pseudoephidrine HCI - but with no luck! My coughing was so bad, my eyes would hurt. I had terrible headaches. All this in a month. I was so dejected, I stopped taking everything but the Singulair. I was still going into fits of coughing! All day, all night - it was affecting my work (I'm a teacher - so I was constantly scaring the kids by erupting into a coughing fit that ended with me spitting up mucus and my eyes watering). My sister had been on Singulair and she told me one of the side effects was weight loss. I guess my coughing and spitting up mucus worried her; she looked at the side effects again. She told me two of the side effects were headaches and coughing. Needless to say, I've stopped taking it. I can't wait until it's out of my system and i can get a good nights sleep