I have a 15-yr old. She's been taking singulair since she was 7....

I have a 15-yr old. She's been taking singulair since she was 7. These are a few of the things that I have noticed over the last year but ignored because I too, as many of you have, thought it was because she a teenager. 1. Stomachache .. she complained all the time. Thought it was nerves because it was usually before she went to a training session or game. 2. Restlessness. 3. Headaches. 4. Moodiness. 5. Tired. Fatigue. Weak. Even after she gets hours and hours of sleep. Figured it was because her schedule is whacked. We've had fights over her not going to bed at a certain time. 6. Menstrual cycle changed last fall followed by acne when as before she was perfectly normal with clear skin. Recently put her on BC because of her hormonal change. Blood tests showed she was normal. We tried it anyway to regulate her periods. Took her off of it after she had her period for 3 weeks straight. Probably won't put her back on BC since taking Singulair might be the problem. 7. Tired all the time. Falls asleep in class. 8. Lost interest in her favorite sport which she rocks at. Thought it was because of a 2-month down time due to an injury. 9. Several times, have seen signs of depression but when confronted she says no she's fine. Depression is probably from being unhappy with her appearance. Being on the pill made this worse. 10. Doesn't want to go to school. Whereas before not a big deal. Most kids don't like school, but lately, she talks about how much she hates it. Usually excited to start the new school year, this year not so much, more like dreading it and her attitude hasn't change about it. 11. We argued last week and it was the first time she screamed at me and told me she hated me. She's never done this before. Her thoughts and moods have been horrible but they come in spurts. After reading everyone's experiences, I am taking her off Singulair. I know it's not an overnight cure and will take some time, but I just want my little girl back. I find it strange that this all occurred within the last year even though she's been taking Singulair since 7. Do you suppose it's in teenagers and puberty?