Becky,

The visual problems you described, including double vision, are more likely
Graves'-related rather than "another symptom of hypothyroidism".  They are
very common to people with Graves' Disease.  Even though you have had a
thyroidectomy, you still have Graves' (and always will).  It is the
antibodies which are attacking your eyes and you should see an
ophthalmologist who specializes in Graves' eye disease or has experience in
successfully treating Graves' patients.

----------