Keeping rooted in the present in the face of past realities I have remembered at least 4 past incarnations, two being particularly influential throughout my current life before the memory of them. I had been cleaning my psyche and spirit during this time, but I still had a hard time keeping rooted in the present with all these different realities suddenly apparent. 

I thought I was ready, as I had been studying reincarnation and the possible implications for years before the memories started. Once they came, it was unlike anything I expected. They were visceral, real, encompassing and completely immersive. I could see so many parallels through them all, and deeply rooted throughout my current incarnation. It began to be too much, and I found it becoming hard to keep rooted in the present. 

I started to wonder if I really was just living the same mistakes again that I saw reflected in the most vivid life, and became scared I would suffer the same pain no matter what I did to stop it. I desperately wanted to seek advice, but had no one near me at the time that I felt would know any answers. 

So, even though it is years past now, I have found this forum, so I ask those who may know from experience: 


How do you keep rooted in the now when all your pasts are constantly running through your mind, sometimes as clear as this moment?
How do you keep this present clear, and not let the other faces and experiences overlay everything?
Do vipassana, a retreat if possible. In every moment you have a memory, know that it is a memory, know about feelings which are coming up and so on. Your mind is in the habit of believing the images, but in fact what you see is just mental noise. Maybe you had past lives like that, but it does not matter (I bet you think it does matter; that's exactly the power these images have over you). The training in returning back to the present moment (by acknowledging whatever is happening and letting it go, time and again) will gradually break the attachment of mind to those images, so you will be able to stay more stable even if these images come.

Whatever in the mind is not a hindrance to be present, if seen clearly for what it is (body sensation, feeling, mind, mind object -- technically speaking); present cannot be destroyed but we are sometimes unable to tune in back to it, and that's why we train.

As a side note: if your condition is psychiatric (you are not able to take care of yourself in regular matters, often can't distinguish hallucinations from reality etc), do seek proper treatment first.