Sitting still might help.You can add an affirmation as well before the med,something like "I am now practicing void meditation."A trance for starters might help as well.If any negative thought about your past life hits you that you can deal with,then do it, do not ignore it.There is a reason those bad boys come around so we deal them.Do Freeing the Soul meditations for 40 days straight.When you finish it,there should be little-or no-negative thoughts which should be very easy to deal with.?