Ok so you need to go an speak with an attorney in your area to discuss hiring him or her to represent you in this proceeding.  It is unclear here how you answered in the first place.  You always have a right to assert your Fifth Amendment rights against self incrimination but what you do not want to do is to perjure yourself by answering differently in a question from the first time around.  So your attorney needs to obtain a copy of your first testimony and you need to discuss with him or he your concerns.  Your discussions are covered by the attorney client privilege but your attorney can not support your perjuring yourself on the stand.  Good luck.