Step one is making sure you're someplace safe to regress!!! I've been where you are right now, and NOTHING is more important than making sure you aren't in danger or in a position to get hurt.
After that, you could try going to the kids section of the local library. They often have a pet and bright colorful themes, and lots of little books. Grab yourself a handful and just sit on the floor in the corner or something and let yourself relax into reading. Sometimes they'll also host movie watching with cartoons or kids movies.
If your shelter is like mine was and you get your own room, you could lock the door and build a blanket nest. Probably not enough to make a fort but you can play on your bed, or have a lay down and day dream.
I hope things get better for you!!