Past lives come through by spirit. When you regress, it means there is some specific insight you want from that last life like a lesson to be learned. Memories of past lives come through in dreams, and also multiple ways and approaches. Are you sure that this is what you want to do? If you are an old soul you might have many past lives and future lives (still to come). Probably best to focus on the present and not worry about the past unless there is something to be let go of healingwise or learned from in that life. Just a few thought(s) here.