If you have a problem at work it’s normally better to raise it informally with your employer first.
You may feel nervous about raising an issue, but employers are often open to resolving problems quickly without going through a formal procedure.
You should approach your line manager first. If you do not feel comfortable doing that, try and find someone else you feel comfortable talking to (such as another manager or someone in HR).
An informal chat can range from a quiet word to a more structured meeting. If a meeting is set up you can ask a colleague to come with you if you feel you do not want to go alone. At this stage your employer does not have to agree to this.