U/E (unemployment insurance) is for when you are "out of work" because of a lay-off or downsizing. You must be available and physically capable of working, and in many states, actively looking for work, to collect u/e. If you were placed on a leave of absence due to a health condition, collecting u/e may not be an option.

If your employer is unwilling to accommodate a disabling condition, that may become an issue under ADA, the Americans With Disabilties Act. I only bring this up because it sounds like your doctor has released you back to work from a physical condition that has resolved, but that your employer does not wish to allow your return for reasons based on a different health condition you had before the injury. If this is the case, and the reason they do not wish to bring you back to work is a pre-existing mental health issue that you had before your disabling injury, then I would probably seek the advice of an ADA attorney.

It is hard to tell what your disability is, as you have not described an actual on-the-job injury. However, if what I have described comes close, you may have ADA issues with regard to returning to this employer. I say this because if you have been disabled on a worker's compensation/on-the-job injury, your employer has no grounds to not accept a full-duty release to return to work from your doctor.

Social security disability becomes an option when you are no longer able to work, period. It does not sound like you are a candidate for SSD at this time.