Many vets don't know how to properly care for the native amphibians because they are not trained with them. My vet saved one of my White's Tree Frogs lives but couldn't help me at all with my toads.
Get a small bin and put a water dish enough to soak her in the water and then get a clamp light of a UVB bulb and place it over the toad for 4-8 hours. It might take a few days to see any results.
Your toad going dormant is something that some toads do naturally and waking them up a herpetologist told me could potentially kill them from stress. If they come up offer food and water and keep the tank running just how it was when the toad left. It may be hard but let the toad rest for a while and if you need to maybe every 60 days check on it and carefully dig it up.
What humidity is the toad kept at? Toads are not desert dwelling animals they like relative humidity like around 55-65. This will help them to be more active.
You can feed them a variety of insects at a time like you would eat dinner. Crickets and Earthworms and Waxworms could be a great meal all at once. The waxworms are like fries you don't want to load up on fries they are a side so only use them sparingly like 5 would be good. If the toad goes dormant like this it will help the toad retain weight because waxworms are fat building. You can use butterworms and different varieties of crickets and the Phoenix Worms. Maybe it's connected to the diet.
You can order insects at Josh's Frogs they are a high quality company and are very polite.
Sent from my BLN-L24 using Tapatalk