Singulair and travels

My daughter was recently put on singulair in october. She has always taken asthma medication since she was two years old.She currently takes advair(500 mg), zyrtec, nasonex.,ventolin . She had a rough fall with her asthma and the allergist put her on singulair and zantac. She is a tennis player who travels around the country playing tournaments and ever since starting the Singulair she has been sick and unable to compete.She has been on four rounds of antibiotics, and she has had a catscan, and all of the numerous bllod tests. We have had her to the DR.S eight times since October. She has also been on prednisone 3 times this fall.Last year she never went on prednisone or had any antibiotics.Her complaints are stuffy nose, sore throat,chronic cough , andno energy. She has symptons for about 12-14 days , then she has about 4 good days and then the cycle starts all over again.If anyone else has suffered from any of the same complaints i would love to know.