I am 30 years old and I've been on Singulair for about 2 1/2 mont...

I am 30 years old and I've been on Singulair for about 2 1/2 months now. I noticed about 2 weeks after taking it that I started getting a pain in the left side of my head accompanied with shortness of breath. Within weeks I started having rapid heartbeats, shortness of breath, dizziness and slight hallucinations (like shadows out of the corner of my eyes). I would experience these episodes for only about 5 seconds at a time. I also noticed that I my ears were ringing a lot, and I was having leg and foot cramps more frequently. At first I thought these were panic attacks because I am in the process of moving, and have been under more stress than usual. I now think it could potentially be a side effect from this medication. I woke up 6 times last night with all of the symptoms and was considering going to the emergency room. I am going to the doctor today to find out what is causing these problems and if it is related to singular. Today is the first day that I am not taking it.