Sweet innocent child symptoms and conditions

My son has been on Singulair for about a year and a half...it really seemed to help his allergies...at least at first. This winter has been very dry and I have been having to give him other over the counter allergy medication as the Singulair isn't helping much. He also started losing weight..just not hungry. At first that was ok as he needed to lose a little but then he was getting too thin. He wasn't eating much at school but refused to take a lunch from home. I took him to the doctor just recently to see if he was physical ok since I didn't know what was causing the weight loss. The blood testing showed everything was normal and I just told him he had to start eating better...he has somewhat...but also he finally told me he has been feeling very depressed...seriously depressed and having suicidal thoughts too due to some kids picking on him at school.

I knew there were problems as he complained alot but I had no idea it was this serious. I have taken him out of that school. Right now I don't know if the Singulair could be adding to this depression or if its all just due to the bullies. While he complained a lot he never acted as if it was bothering him that badly or I would have gone to the school about it. Anyway I stopped the Singulair and am going to see if his mood improves or not. After reading some of the scary posts on here regarding the side effects I am wondering if this is a good idea stopping it or not. I am waiting for a call back from his doctor on it. Since its once a day..its kind of hard to wean them off of it...but I could cut it in half ..do that for a few days, then cut it smaller and so forth. His is chewable so I could do that with no problems. He is 13.