I'm sorry that you're feeling this way. What makes you think that feeling this way will magically end upon their death? Every time you fail or do anything you think they will not approve of for the rest of your life, you will feel that shame and smallness you're feeling now. Because YOU give these people their power.

I know these feeling are real to you, and therefore an issue. I also know that there are people out there that are incapable of expressing themselves in a positive way. Ie, Mom I got a 98 on my paper and mom replies why didn't you get 100.

You are 48, old enough to express yourself in a mature meaningful way. If your parents do say or do something that makes you feel, call them on it. Let them know how this continues to negatively impact your life. If they will not respect you and your boundaries cut them out of your life.

If a hot topic comes up that you know you'll disagree upon, why even enter into the conversation? Just agree to disagree, neither of you will change the other person's mind.