Am I more likely than average to have another autoimmune disease?

Yes, if you have one. If you have one autoimmune disease you are more likely than average to have manifestations of other autoimmune disorders.
Maybe. You may be at increased risk of auto_immune diseases if you are a female, have a personal or family history of auto-immune disease or if you live in colder temperate regions. Other factors include viral infections, chemical exposure, and ethnicity.