Sometimes I Don't Stutter? Sometimes it's worse?

Sometimes I Don't Stutter? Sometimes it's worse? I recently got a retail job working behind a cash register, and working in front of people again has made me realise how bad of a stutter I have. However, I noticed that in some cases, such as talking over the phone or taking drive thru orders, I can hardly speak at all. Other times, when I'm off work and hanging out with my friends, I notice I hardly stutter at all. Is this normal?