I think it's all too easy to stress about the whole unwritten rules thing. I know I'm prone to it. Often I think I'm on the outside looking in and it's not a nice feeling but there are many others who share the same feeling.
I know it's not easy for you but is there anything you could help others with? Are you coming over as a bit too over enthusiastic about what what you want/need at the expense of others? Saying that, I'm more the sort who will do things for others but can sometimes feel unappreciated or that I've fussed too much and not really helped at all.
You need to look for things you might have in common with the people and use this as a basis for your approach.
Hope this helps
"With a foot full of bullets I tried to run faster but I just hobbled on to the next disaster." (From Peter and the Test Tube Babies song Foot Full of Bullets