Welcome to the forum and it is so very brave of you to reach out and to share how you are feeling about your "dreams" and about the "other people" in your life. Firstly it is a really safe space here and you can share how you are feeling, get some support, some comfort and some care here, we are here for you to help you through these times, you are not alone.
I know it's not the same but I wanted to share something kind of similar in that when I read a book, I get so invested in the characters, I become attached and also think about other story lines that are not apart of the book and wonder and create scenarios that are not even true or once again, apart of the book. Then when the book is over I am almost grieving the loss of my friends and feel sad that it is over, it only ever lasts a day or two but I feel like I have lost my friends.
I think it is human to want and to create things that we don't have, whether that be the perfect friend or the perfect family or even boyfriends and girlfriends and let our imagination and thoughts create a world where we do have the love and the acceptance or the joy that we are perhaps not getting from our "real life".
I see that you are worried that the people in your, lets call it "fantasy life" are starting to get blurred with the people and situations in your real life, the fact you are aware of this and that you are trying to make a line as to what is real and what is not shows that you are aware of what is reality and what is fantasy. I guess the more time you spend in your fantasy world it is probably likely that it does start to confuse your reality life.
It is really nice to meet all of your "friends", thank you for sharing that with us and if you do want to share some of the things that these "people" give to you or make you feel that would be lovely to know.
I can hear that you are worried that these people will stay with your for the rest of your life, can I suggest though that as you get older and different people come into your life, as you grow and have more life experiences the "need" for these friends may no longer be there. Maybe when you are working or have a family of your own one day or travelling or whatever it is in life that you find yourself doing, that you may not have the time or the need for these people anymore. In saying that though you may always have them just around, that you think about from time to time, and that is fine too.
It is great to chat to you Nerissa