Here are two tips that will help you better understand your assumptions and core beliefs:
Identify the events linked to the start of your sadness or depression:
Another important way to uncover your negative core beliefs is to think about what was going on in your life around the first time you were experienced a long period of sadness or depression. One thing you can look for is a match between what happened in that situation and what your specific assumptions and core beliefs are.
However, remember that no matter who you are, it’s important to look at both your needs in relationships and your needs for success & enjoyment in other parts of your life.
Examine your childhood experiences:
In general, the strongest core beliefs and assumptions develop earliest in life from interactions with parents and other caregivers. They also develop more from interactions with school peers and friends. Your history of adolescent and adult romantic relationships is also something you should consider because they could contribute to the development of some of your beliefs about yourself and others.
How do you think your past has affected your present?