While most with lupus have positive ana having a positive reading does not mean you have lupus. It suggests that you might have lupus or another autoimmune disease.
Episcleritis is also commonly associated with other autoimmune diseases so it could fit that you have some underlying condition causing the inflammation.
All questions you should ask your doctor.
MCTD (SLE Lupus, polymyositis, scleroderma). Diagnosed 2005. Kidney, liver, GI tract, dysphagia, raynauds, barretts esophagus, quadriplegic in 2005. Recovered and now active in downhill skiing, golf, hiking. Meds: amlodipine, benezapril, omeprazole, potassium, folic acid, vitamins, maxide.
Remain Optimistic and you can overcome.