I have a Manouria emys phayrei (burmese black mountain) and mine was similiar to yours when I got her. I looked at it like this:
these guys lived in hiding and away from preditors all there lives, not seeing humans. So when captured the see us as very large preditors and have fear. Large hands reaching at them, new surroundings, travel is all scary.
With mine I created a large indoor enclosure, covered, at a constant 80 degree temp, with a humidifier (from walgrees $10) going on for 2 minutes every hour, and a moist base 1" thick of spag moss, cedar mulch, coco fiber over the whole area. Then I added a large pie pan pushed into the base and and a basking light above it, along with some plantings in pots. She liked this base (substrait)and burrowed into the base in hiding areas in the corners. I would let her sleep/hide for 22 hrs of the day then at 3:30 I would gently pick her up and put her in the pie pan with warm water up to her nose, then I would get out of the area and give quiet and have cardboard up over the enclosures plastic walls (so she could see me). She starting loving this and when she pumped her throat and put her back legs up (flying) I knew she was happy. I then would leave her in ther as long (sometimes 3 hours) as she liked (never watching her directly).
At the point of her leaving the pool I introduced a plate of:
sweet patotoes, collar greens, crushed strawberry, almost rotten banana and thats it. I just placed it in front of her. Then finally she started eating everyday and the rest is history.
Probably the main things are they do not liked to be watched while eating at all, they are very,very slow and careful and are easily spooked.
I love my black and she is slowly coming out of it. It takes years for them to come around. They are not like any other tort on the market and are not for children or can be taken as a pet.
I still have to find mine in the substrait and put her in the pool or she just stays hidden and she is 1 year old and I have had her for 3 months. If you live in a tropical area she can go outside for a time each day.
I take alot of research and time for this species and if you get to a point of not wanting yours, please let me know.
good luck and hang in, its not about you and your needs with this species!!!!!