You sound like you might be having trouble with anxiety and depression to me but only a doctor can correctly diagnose. How are you sleeping and how is your appetite?
I think you should make an appointment with your GP and explain to him / her what you just have in that post. Has anything happened recently to make you upset? The doctor will most likely ask these questions too.
If needs be you can take some time off work or cut down your hours or something. Try not to worry too much, I know it's difficult but help is out there.
Feel free to message me if you'd like a chat :)
xx