I have a tendency to blurt out random things at random moments. I have a rather eccentric personality. I also have a similar thing as you although I only focus on a few of my ideas and write down bits of information on the ideas I like.
I think my 'tendency' would be the same as yours to an extent. I'm always getting ideas in my head-- usually the middle of a story, though. Either the middle or end. I can never get the beginning of one. But I always end up finishing. But what I think you should do-- is try and make story ideas into one-shots. That way, if you ever get an idea for the story again you could just change the ending a little and continue it at your own pace. Also, try keeping a pen/paper with you, if you ever get an idea and you can't type it out. I tend to keep a sharpie with me and write ideas on my arms. I'm not sure how that helped, but I really suck at advice xD <3 Saito