When we work through feelings, we work with our memory. To understand what it is that you're doing, it's good to know about our two kinds of memory.
Explicit and Implicit Memory
When talking about our memory, we usually think of our memory for facts. Those facts can be things that happened to us, or things we know because we heard or read about them. Things like names, faces, appointments, what happened to us, things we watched happening, numbers. With this kind of long-term memory we normally don't remember things from before we were about 4 years old.
This is called "Explicit Memory," because we know these things explicitly.
There is another kind of memory, that is about knowing how to do things, about skills we have, routines, habits. It is also about the ways we emotionally react and relate to people. We often "just do it," so we hardly notice were it's coming from that we do.
This is called "Implicit Memory," as it is implicit, we know how to do things, but are not so much aware of what exactly we know.
With Implicit Memory, there is no such limitation of not being able to remember things older than when we were around 4 years old. It may seem special when you first encounter feelings from when you were a baby, but there is nothing especially difficult about going into feelings from that age, actually.
Working through feelings
Recalling past events, which is Explicit Memory, can help somewhat with working through feelings. But this is not where the emotional reactions are that we might want to change. Those are in Implicit Memory, since they are things we do, rather than recall. This requires a different approach.
To deal with our emotional reactions, we need to focus on feelings, rather than recollections. When we focus on a particular feeling, it can start changing or dissolving. Then, another feeling will come up, which does that also. When we do that, the feelings coming up will belong to a single situation from out memory. When we had them all, the memory, and thereby the reaction pattern, will go away entirely and permanently.
What happens in the brain, when you do this, is that the particular memory that you access gets in a kind of "loose" state. When you have "loosened" sufficiently interconnected feeling memories belonging to a single situation, these dissolve completely. You have then worked through the feelings of that single situation.
A problem that happens a lot here, is that only part of the feelings belonging to a situation in memory get addressed. These then seem to dissolve at first. But when not the entire structure of interconnected feelings gets worked through, what seemed to dissolve can return anyway at a later time.
The forming of Implicit Memory
Whenever you act or feel in a new way, during the day, that is bound to get into Implicit Memory. The actual getting the new patterns into Implicit Memory happens during deep sleep (not REM-sleep). For most people that is during their night's sleep, and not while they're taking a nap in the afternoon.
You can sometimes notice that, like when you're learning a new skill. While doing things that are new to you, you can notice a difficulty with that. But the next day, after a night's sleep, doing that very same thing has become easier. It seems to go by itself. That is because it then has become a skill and comes from Implicit Memory now. It is gotten there while you were asleep. It's probably where the expression "sleeping on something" came from.
Other terms that are used
There are other terms people use, particularly when it comes to Implicit Memory, namely the "Inner Child," the "Unconscious" and the "Ego."
Here, the term "Inner Child" is used to denote memories from Implicit Memory where you can feel that they were from when you were a child. Such feelings stand out for working through, because they are clearly from a time when your brain wasn't yet fully developed, so that you'll develop more mature reactions to situations after working this through.
The ways that we emotionally react are said to come from our Unconscious. Mostly, this term is used for when we don't quite notice where emotional reactions come from. It is basically emotional and relational reactions from our Implicit Memory. They can belong to the Inner Child, but can just as well come from situations experienced as an adult.
Especially in spiritual circles, the term "Ego" is often used. It doesn't quite mean the same as how the word "Ego" is commonly used, as meaning that a person is doing something in a way as to increase their sense of self-worth. It is also different from the term as used in psychology. It is comparable to the term "Unconscious," in that it is about the emotional and relational reactions from Implicit Memory, and particularly from the Inner Child.
Usually, the "Ego" from spirituality is taken to be dysfunctional. Not only does it make people do things unnecessarily to boost their self-worth, it is seen as overly habitual, and full of reactions to solve problems in the psyche that can better be solved in other ways. It is seen as insulating a person from their real self.
The word "Ego" isn't used here, because of the overly broad meaning of the word as it is used in spirituality, and the confusions it can cause.