I feel your pain, a similar situation happened to me. Please do not feel guilty about not telling anyone, you were so young and didn't know what you were supposed to do. Hang in there, and know you are not alone.
I was three years old when it first happened, and it was my older next door neighbor (about 7yrs old) thought it would be fun to mess around. what did I know. This continued till I was about 5 or so. No one knows of this, I just lived in silence. It was not till I got older that I realized how much it affected my life, in a negative way. I carried around a feeling of guilt and shame, but it was not my fault.
As time passed by, the pain of my childhood began to fade. I finally didn't feel scared and helpless anymore. But that feeling didn't last long, because something else happened.
To make matters worse, I let a person who I thought was a friend stay with me in 2004, and he raped me. He stayed with me before, so I thought nothing would happen this time around but I was wrong.
I have been carrying the pain with me since then, and trying to deal with it everyday. All the pain from my childhood came back intensified, and new ones were created. Half of the time I wonder how I made it this far, because no matter what I do it hurts soooo much. I often wonder, if the pain will ever end.
I have barely talked about my childhood expereince, and only briefly mentioned my rape. It is not that I don't want to heal, but dealing with it has been a horrifying experience. This is the first time I am telling of my painful and unfortunetly unforgetable experience. I keep hearing that healing takes time, and the pain will start to fade. I am still waiting for that day.