Your life will continue to be horrible until you totally separate from your mother and live an independent life. You can’t fix her, you can’t help her, but a few more years with her and she can destroy you. Listen to your therapist. Just leave, don’t tell her you are going to leave, sneak away, make no contact, block her on everything, don’t return to places she expects you to go, which means a new therapist. Hard at first, but you can do it and your life will gradually improve. Your mother may have been homeless when she lived in your dorm room, but this was also a nasty attempt, unfortunately successful, to prevent your independence.