D.B.
Disabled kids often have these types of problems. With anxiety, depression, sensory processing and autism all together - I'd be surprised if she wasn't having an issue like this! Do she have an occupational therapist or a behavior modification specialist you can work with? You would be much better served by working with local people who are familiar with her diagnoses and medications.
I am not a big fan of potty training at 11 months or 2 years - I think it often fails because the kids are not developmentally ready. In fact, she may have problems with the sensory aspects of knowing her bladder is full, even at 4.5 years of age.
Talk to the pediatrician, her therapist or her neurologist about what services would be best for her.