It all starts here:
our mind has an ability that our body does not, to live in all 3 times: past, present, and future.
Our thoughts evaluate past experiences to judge whether what we are experiencing in the present or will experience in the future is good or bad, whether we will succeed or not, whether we will be enough or not. This is where the mistake lies, this is where many people find their blocks, blocking the resources they have to be better than they were or have been before. Many people even go through experiences of success and overcoming challenges, but, just because it's a victory, instead of seeing it as a genuine achievement, they view it as an exception, a random and divine gift, or anything that suggests undeservedness or lack of personal ability.
This happens because our mind has an ability that our body does not, to live in all 3 times: past, present, and future. It's during this process that your decision on which tool you will use comes into play, but there's an important battle here: between what you want and your beliefs (which can be limiting).
Here comes into play an important resource you have, which is innate: your creativity, and for this, you use imagination. Being creative allows you to invent things that don't yet exist, in your favor, things and reasons that propel you in the direction of where you want to go. The problem is that imagination can also create anxiety, anger, regret, fear, depression...
The past is just a library, but it will also be your future if you live in it. The now is your laboratory, a place to experiment with what you want to experience. The future is your reward. In other words, who defines your future is your present, which can and should use your past as a reference but not as the source of truth, because no experience you've lived has covered all possibilities, so an experience that was bad could have been good and vice versa. People marry more than once for this reason, start new businesses after failing, rekindle relationships, forgive, don't give up, etc., simply because they know that even having made a mistake at some point, they understood that in life there are always at least 2 paths, and always a chance to make a mistake; however, they manage to have the humility to know that the mistake is just a teacher saying what and where they need to improve.
Thoughts will always relate to your past. So, use this now as a resource, don't waste energy thinking about a wrong future.
That's why our EGO is always our worst enemy. Our EGO is the part of our personality that lives from our past, it needs to show its value by drawing its content from there and projecting it into the future. It pulls you out of the present and reality.