You need to come up with something meaningful to do that is away from this fantasy. Think and actively practice your DBT stuff. Try to let the thoughts be clouds, etc. Take a mindfulness walk, a warm bath or shower, clean your fridge, anything that can take your mind off of it for a while. Try meditating in bed or before bed. Get online and play games or play the games on here. That is the only suggestion I can come up with.