Empty/strange feeling in chest?

Empty/strange feeling in chest? Today has been an awful start. I've got this empty/strange feeling in my chest and I can't get rid of it. I don't know if it's the cause or not but my stutter has been horrible today and it's painful. I've tried breathing techniques, slowing my speech, extending my pronunciations and it's not working. It's only been 2 hours into my 9 hour shift and I want to cry. I work in a call centre and get call after call with no gaps. Today is tough