What's really real? Sometimes what you imagine is real is realer than ANYTHING.
You dwell on it, live with it, examine and re-examine, define, re-define, and spent tons of time on denying whatever it is, but the more you think on it, try to handle it, the larger, messier, more complicated it becomes.
Beware -- this is the way an obsession gets born. It distracts you. It keeps you awake when you ought to be sleeping. Like -- am I too old to wear hot pants? Why hasn't my agent phoned me? Hey, was that little cramp in my chest my heart?
Some obsessive thoughts are worries. Others are fantasies, like, gee -- I could have made a lot of money on that idea! Golly, I could have been a star.
How to stop it, nip it in the bud, blap it, bomb it out of your mind?
Write it down?
Grab a pen, a piece of paper, name it -- spell it out. Pin the specifics about the thought on the paper -- the phone call you ought to make but haven't made -- you'll phone on what date? Put down the name of the person, a summary sentence, what you need to do to fix/change/end what you've been thinking over and over.
Or skip writing it down. Just phone someone, anyone, and mention what you've been thinking and when you hear yourself verbalizing whatever it is -- hey, you'll realize it isn't so awful, so important, or so urgent. If you hate to phone, mention it in an email, or tell the mail man, the delivery boy -- say -- I've been so busy worrying I haven't found out how you're doing?
Any obsession is like a rock -- too big, too heavy to pick up. You can't move it but you can pick up something nearby -- a pebble, a pinch of dirt, and ponder it. Put it next to that big old rock and hey -- the rock's just an old part of the scenery that, once upon a time, was dirt, a pebble, or maybe a bunch of 'em that got stuck together and -- hey -- whatever you were obsess-ifying over, is gone.
Go look in the mirror. Wear the hot pants. Comb your hair. Smile.