Fear of Commitment

I don't think I've always had a fear of commitment. Not just in relationships, but in everyday decisions.
 If I order something at a restaurant, and then think I might change my mind, I don't call the waitress back and bother them to change my order... I live with the decision I made.
I haven't had a lot of true relationships with guys in my life but, however 'high school' the relationship was, it usually lasted close to a year.
I've always known I wanted to be with someone and get married and own a home.
Ever since that was pulled away from me I've denied that I've had commitment issues. I kept saying that I just wasn't ready to let it go.
But now, even though I feel I've moved past a lot of feelings, I still find that I push people away unnecessarily. I'll look forward to meeting someone, have a lovely conversation, and then on the drive home I pick out all the things that were wrong with them and decide that I can't live with them for the rest of my life. Sometimes it's justified. Other times I feel like it's a defense mechanism.
Usually it's stupid things like 'They like different music than I do', 'I didn't get to read a menu because they kept talking to me', 'He was an inch shorter than I thought he'd be'.
Other times they loudly voice opinions on parenting techniques and give me 'advice'.....no thanks.

Is it a fear of commitment, or just a matter of not finding someone I click with? Shouldn't I give people more of a chance?

Commitments at home aren't going well either. I think I do pretty well to stick to my guns as far as discipline strategies, but the thing I can't stand that Toby still does is nurse to sleep. I'm getting to the point where I greatly dislike breastfeeding. It hurts my back and my neck and my shoulders to lie beside him in bed when he  takes half an hour to decide if he wants to sleep or not. I've said on several occasions in the last year that I don't like doing it and that he can hold my hand and cuddle, or i can leave him alone to sleep by himself.
It just results in a lot of screaming instead of sleeping. On both parts. From the beginning I've always rathered him to be comforted to sleep rather than lie there and cry. I tried to ignore him on a couple of occasions, and he just wakes himself up more instead of wearing himself out and then takes twice as long for me to calm him down again. Now that he's old enough for words he just screams for me to come back and that he please please just wants to nurse, and if he really isn't happy he just gets out of bed and runs away.

And so is it a fear of traumatizing my son for bedtime, or a fear of committing to what I say I'll do?

I've been saying I'm going to start a business for ages, but then I can't commit to it because, like, what if it's successful? Then I'll have to, like, keep up with it.

I can't even commit to going to bed when I say I"m going to... I got out of bed to turn my computer off... and there I am an hour later typing my brains out lol.

Ok... NOW I'm going to bed.... maybe....