What helps calm your nerves?

What helps calm your nerves? I'm based in the UK and the past four days I've been vert jumpy and fidgety and I believe its making me stutter more than usual and it's causing me to panic more than I usually do. Is there anything that helps calm your nerves ? That maybe isn't alcohol, smoking, etc? Medication is fine though and other methods you may use Edit: I forgot to add that I usually go through these bad periods and I usually pass over them but I would like to not have to suffer for days or weeks before I am back to "normal" again. I always feel like quitting my job when I'm struggling like I have been recently.