Nervousness-- PLEASE HELP

All day today I have had extreme anxiety. Everything sounds loud, and I am extremely irritated and bothered. This is not emotional, or hormonal. I'm not worried or tripping about anything. I got about 9 hours of sleep before I came to work. I feel aweful, very on edge. This anxiety is very physical. I feel like my head is going to explode, I can't sit still, and am dizzy. My heart is beating very heavily and my breathing is shallow. I don't know what's wrong, I just feel very anxious. I'm 20 weeks 2 days with my twins, and something feels very wrong. What do I do? Please help. I don't want to go to the ER just to sound stupid.