Cara,
The best way to see yourself, is to look at others. You would be surprised at how alike we are in many ways. Many people do what you do, and avoid large groups. Oddly though, it is much harder to manage conversations within smaller groups than it is to be conversant in large groups. In small groups the path of a conversation can be limited, and subject to the vicissitudes of the whims of natural digression. That can make it hard to keep up, and sometimes makes group members feel at a loss and inadequate. In larger groups conversations can take on many forms, but when one is addressing that group entire, the subject will remain static and relatively inflexible to some degree. It is for the performer that anxiety creeps in and problems occur. A true dichotomy!
Your worries are just related to performance anxiety. I would say you love to engage people in conversation, and are probably an excellent conversationalist. I say this because you seem thoughtful and considerate of your audience. This would naturally translate into your conversations, making them measured, and thoughtfully well-composed.
What are your favorite topics? Tell me a subject you get excited about. Something that really gets your tongue wagging.
As to your comment about "as you can see, I am not that bright" I would say you have a gift for introspection, and at this you are a very hard taskmaster. People who are introspective possess an ability no stupid person has. One negates the other, ergo, you ARE a bright person!
It seems, too, that people where you work are diligent and not very conversational. From what you said I would glean that - in conversation - you are a "gap-filler," that is someone who is uncomfortable with excessive silence, and seeks to fill it somehow.
I love to be alone. And I love silence. Silence affords all manner of things that human generated "white-noise" covers up. Right now I am listening to the wind rushing over the house and making its way down the flue into the gas furnace. The house is creaking, and these noises are serving to remind me of going to a netball game with my cousin Elizabeth in the winter of 1964. Thinking about that, I can remember riding on a blue train to Clayton, where the match was held, and on a red train on the way home. The furnace fan is making me think of the noise the electric trains used to make while standing at the stations. I would listen, while sitting or standing in the carriage, to that noise, and sometimes wonder why it was that passengers never seemed to speak. The carriages were always devoid of conversation. A peculiar quirk of human nature.
In larger groups and parties, I try and find people who never shut up. That way I don't have to say much, and I am allowed to get bored. I know you can tell me some stories about people that drove you nuts because they just would NOT shut up!! I would like it if you told me one of those stories.
You asked me about meeting the "right people in life." No I haven't. When I talk to people, the conversations always seem to go towards some kind of issue I am passionate about. The problem is that my passion is rarely shared by others, and I often fail to find my own "off" switch! It is because of this that I have developed strategies to overcome this. I find people who talk a lot, and who are good at it. I also try hard to be around people who have some kind of academic interests and intense curiosity so that I can involve them in my own academic musings. Generally, people like that know they have a lot to offer intellectually, and are not shy to offer it! That keeps me safe, and away from embroiling myself in situations I cannot handle well.
Truly, as you are engaged in a group, bear in mind that others in the group have similar anxieties, but handle them in different ways.