Anxiety is a feeling of unease, worry or fear1 or and is often a response to something that is causing us doubt or uncertainty.
We all experience anxiety at certain stages in our life, but if it is prolonged and intense, this may cause mental health difficulties. Anxiety can affect our mind (e.g. a feeling of dread, difficulty concentrating); body (restlessness, nausea) and behaviour (withdrawal from family and friends).
Reference:
1 Mental Health Foundation, https://www.mentalhealth.org.uk/a-to-z/a/anxiety, Accessed 10th January, 2022