Intestinal infection symptoms and conditions

I have been taking singulair for about one week now. A few days ago I noticed abdominal and intestinal pain. Last night I got abdominal pain and fever. I called two doctors and they said it was probably not the singulair. But then I read their web-site for side effects. And one is possible intestinal infection with fever. I can't believe this. I don't understand why the doctors would not say anything or take you off of it. Thanks

I am 61. I was recently prescribed levaquin for an intestinal infection. Began having rapid heart beat, trembling, shortness of breath, floaters in my eyes, itching, thick tongue, lips tingling, irritability, sweating, feeling of brain fog. Felt like I was having a panic attack. Stopped taking medicine after 6th day. Now I can hardly move my head. My left shoulder and neck are hurting very badly -- feels like muscle spasms. After reading these posts about levaquin, I'm sure that is the levaquin has caused these problems.