Here's my thought: Let's say right now you were presented with a piece of paper that says IslandOfApples: you are gifted. What would that change for you? It sounds like you are saying in your head you would have a valid reason for your feelings of difference.
From my perspective that sense of validity of your feelings doesn't come from a piece of paper with an IQ score on it. Because of course there are a range of feelings that people x number IQ can have. Many will feel nothing like you feel. Some who have a totally different IQ will. Having that IQ doesn't take away the experience you had of feeling alone as a child and it won't make you less along right now.
If you feel discontent or loneliness in your life now that's what I'd focus on. A little bit of therapy to come to terms with your feelings might help. Putting energy into finding people you can connect with would also help. Most adults don't join clubs based on IQ - they meet around shared interests. What are your interests? It is very likely if you focus on your interests you will find ways to connect with people. Think about activities like: volunteering, book club, chess club, etc. Putting the same energy you put into online activities into real life activities is the road to building those in real life friendships that offer the possibility of real support.
