Hi, I m a 35 year old woman who has had about 10 years of problems with stress and anxiety. The doctor currently has me on celexa for manic depression and anxiety. I am currently on 20 grams. About a month ago I started smoking meth everyday to cope with an attention problem. Sometimes I will not take my antidepressant because I am afraid of having serotonin syndrome or heart palipatations. Just recently when I smoke (I smoke until I feel high) I get tightness in my chest and left arm pain. My heart will sometimes speed up or go really slow usually 50 beats per min. If I get up to do something it will seem to get worsted with lightheadedness and feeling like I might loose consciousnesses. I also have very short breathing. So my question is are my symptoms because of the interaction between the substance or just the meth it self, because of stress and anxiety, or due to a more serious condition. Or is it a combination of things?