The concept of past lives is something that is very widely misunderstood. Lets throw every preconception you have about past lives out the window for a moment and think about this topic with a clean slate.
The central topic you should be thinking about when it comes to past lives, is your consciousness or as i like to call it, awareness or that which knows.
The highest truth there is to know, is that there is only one thing that exists. This is the reason for picking the descriptor "non-duality". The illusion (mara) is how we view the world. We think we are an observer, using our 6 senses to understand things that are separate from ourselves. This illusion is broken when we understand that consciousness/awareness creates our 6 senses, and our 6 senses create all the objects we see. But to say it "creates" them is incorrect, for there is only one thing! Consciousness is sight, is a tree, is an atom, is a wave.
Since there is only one infinite consciousness, we are all the same being. The same consciousness that is typing these words is also reading them many times over in different minds. This is the core understanding of past lives. Every conscious mind that is observing infinite consciousness is the same. Using incorrect verbiage, you could say that every living creature that has ever lived, or will ever live is a reincarnation of you.
Now, that being said, lets use that mindset to directly discuss your meditation experiences.
While meditating I often slip into states that take me outside my current sense of self and into another experience.
You are not slipping into another experience. There is only one experience we ever have, and we call it experiencing the now. You are still caught in the trap of associating your identity with a particular set of experiences, such as the sight of your body, or the opinions that appear in your mind. When you slip into these states where you believe to be in another experience, there is much to be learned! Ask yourself, why do I believe this experience is different from any other experience?
Though I don’t believe this to be a past life recall, I often wonder if I experienced this 2000 years ago in Indian society, would I have consider this a past life? Just like past lives can be consider endlessly varied so can these vivid experiences.
Time is also very widely misunderstood.
Lets take space as an example. I am sitting at my desk in a room in my house. I pick up a picture frame on the right side of my desk and move it to the left side of my desk. Have I created a new space? No. We believe there is only one space, and objects in space can be re-arranged into different configurations. No matter what you experience in the space, it is unchanging and always the same.
Lets take time. I am sitting at my desk right now. I pick up a picture frame on the right side of my desk and move it to the left side of my desk. Have I created a new time? No. We believe there is the past, now, and the future. This is incorrect. There is only one moment, now, and objects in the now can be re-arranged into different configurations. No matter what you experience in the now, it is unchanging and always the same.
We have all only ever experienced now. You can not leave the now and go to the past or the future. Even when you meditate and experience a vision of something you suspect to have happened 2000 years ago, that experience is happening now. You "remembering something that happened in the past" is happening now.
Reincarnation is not one identity becoming another identity through time. Reincarnation is one simplified explanation we give to teach that we are all one being, experiencing many different minds.
There are no past lives for there is no past, only now. There are no past lives for there is only one life, the life of consciousness.
What you see, hear, taste, smell, touch, and think has nothing to do with who you are. They are just experiences you are passively observing. I suggest, in your meditations, to focus less on the contents of your mind, and more on how those contents come to be. What is watching them? What are the properties of that watcher? How is the watcher affected by observing these 6 sense doors?
Congratulations on walking this path. You are extremely close to nirvana. I pray for nothing more than your liberation this lifetime.