It's one thing to be a high achiever; it's quite another to privately sneer at your girlfriend's friends after feigning friendliness because they have the "misfortune" to drive a bus for a living.

Worrying seems like a fairly natural state of being for a parent, so feel free to worry as much as you want.

I do not think it is selfish to want to donate a kidney "only" to family members.

If this is something you'd truly like to work on, not out of a sense of guilt but because you would enjoy occasionally reciprocating, there are a wealth of resources out there for the enthusiastic amateur (you are far from the only would-be blow-jobber whose spirit is willing but gag reflex is weak). You have more options than "no blow jobs, ever" and "regular whole-hog sessions to completion that result in vomiting."

If you don't like potlucks, the solution to your problem is "don't go to potlucks," not "insist other people don't have them."

If your partner asks you if something bothers you, and something bothers you, the best thing you can do is say, "Yes, it bothers me." Otherwise you create a situation where they think everything is fine, continue with the offending behavior, while you build up a secret reservoir of resentment that will eventually come pouring out, to their shock.

Don't let a friend make you feel publicly uncomfortable indefinitely just because they're probably a lesbian.