The dictionary definition of resilience is: the capacity to recover quickly from difficulties; the ability of a substance or object to spring back into shape; elasticity. It's a subject of great interest at the moment because many of us are having our ability to "bounce back" tested by the coronavirus.
A model that comes up a lot is Elisabeth Kubler-Ross' five stages of grief theory, which was published in the late 1960's. Her experience with terminally ill patients led her to observe a pattern of thinking that people go through when facing death either themselves or in a loved one. This theory was later found to apply to all kinds of personal loss including disability, redundancy, divorce and financial problems. It's not a linear process: people can go through it at any pace, in any order and often experience cycles of it.
These are the phases:
25 years experience in helping teams build user centred products and services, now helping digital colleagues learn how to bounce back better than before from the challenges life throws at us from time-to-time.