Most Helpful Guy
You are angry and jealous when seeing them doing what they always have. Did you expect that just because you had a child all your friends would suddenly change their lifestyles? Would you have suddenly given up hanging out and having a good time just because someone else had a child?
I really understand how the changes can leave you alone and missing the fun you had before. But this is something you did (whether by choice or accident) and you should feel no anger at them.
I commend you for choosing your daughter over the lifestyle that used to be yours. Now you need to find others who have children, whether married or single, who understand and share your new lifestyle. I do not know what your circumstances are, but places people can look for the new friends is their neighborhoods, their schools, their workplaces, their churches, etc.