Evilly, does that really matter, finding out whether intercourse has taken place or not ? Some of the worse sexual abuse can take place without there being intercourse.
Nobodyhere, everything you describe probably related to something having happened to you. Something that is very, very traumatic can be blocked out of your mind, you cant remember because you have blocked it out. None of this is your fault, but now you must go and get help. Go to Childline, or a Rape Crisis Centre (which deals with all sorts of sexual abuse). You may not have been raped but something happened that scared the life out of you enough for you to blank it out. Go and get help, before this destroys your life.