Trust

I have the worst case of NOT trusting people. Sadly it isn't just men that I don't trust....it is everyone. I have been hurt by so many people in my life that I just don't trust people and have the hardest time allowing anyone in. Every time I am ready to let my wall down, I seem to get hurt by another individual in this world and it ruins chances for everyone. I know this is an issue with any type of relationship I will have in my life, especially with any guys that enter my life. I think now that I have a son, allowing people in is so much harder for me than it was when I was a single childless female. I am not only scared of myself getting hurt, but I am petrified of my child learning hurt and disappointment this early in his life.
So now my question is.....how do I get over this? I have been this way for so long in my life that I don't know what to do to make this change. I guess you could say I take things too personal and that doesn't help the situation either, but there has to be a way to overcome this right? I fear that if I don't learn how to trust people I will never find anyone and I will be alone for the rest of my life.
I was asked a few weeks ago what my fears were. At first I said nothing, I really couldn't think of anything that scared me, but for some reason this question has been surrounding me on a daily basis. The more I think of it the more I have realized that I truly fear being alone. I don't like being alone at night, I don't like being alone during the day and I don't like the thought that I may be alone for the rest of my life. I have enjoyed being single and focusing on my son (still do enjoy it), but I now fear that I will never find someone (not that I am searching) to be with/in my life and most importantly my sons life.
I look around and see all most my friends who are married with families and I want that. I want that for myself and for my son. I want a male to be in my sons life who is a good role model, who is responsible and enjoys spending time with him (don't get me wrong I have plenty of great guys for Camdon to look up to, but I want 1 in OUR life). I want a male that loves us the way my friends husbands love them and their children.....but having a trust issue isn't going to get me that, is it?