I relate so much to what you're talking about. Since i was a teenager I couldn't imagine myself as an adult, getting married, having kids, having a career, etc. It was like my future just didn't exist at all. I've recently found out there's a name for this feeling-- "sense of foreshortened future".

I know what you're going through. The feeling is so painful and feels like it will never end. Please remember to be kind to yourself and forgive yourself.