Bonding After Release From Prison - From Andrew

Hi all. My son was 4 months old when I was sentenced to prison. He is now 5 years old.
At first, I was placed in a jail near to home and my girlfriend brought our son to see me quite a lot which I was very grateful of.
I was then moved to a jail about 2 and a half hours away from home and the bonding with my son came to a halt. My girlfriend did not have her own transport and could not afford the journey to prison via public transport. Also she found it very difficult to travel the distance with our son because he is on a special diet due to his disability. 
I came out of prison when he was 5 and my son was a stranger to me as I was to him. My girlfriend did stay in touch during my sentence and kept me up to date with his progress and development and sent me photos.
Since I have been out of prison, I am finding it difficult to bond with my son. I feel disgusted with myself for saying it and I do love him, but I have missed so much because of my stupid foolish decision to commit a crime. I paid the price for that, but so did my son who is the innocent party no matter which way you look at it. I spoke to my probation officer about the bonding difficulties because when I attend probation, all they do is ask me how I am. Every time I tell them I am finding it hard to bond with my son and they do or say nothing. 
Prison is prison, I except that and I deserved the sentence. But whilst I was in prison, the so called rehabilitation process was virtually nil apart from some diploma's here and there which I achieved studying. But there aren't any diploma's in there for people being released back in to a family environment after a prison sentence. The prison gate opens and that's you thrust back in to a family home that has changed dramatically straight down the line. Maybe the bonding will come naturally and will come in time. Maybe it is me being impatient? I don't know but I thought I would write in to you and let your followers read what it is like from a Father's and ex-prisoners point of view when a family has been separated in this situation. I am fully aware that it is my fault for getting myself in the situation in the first place, but how many children are sentenced too when a parent goes to prison? How is my crime my child's crime? Regards Andrew.