Depression and Myotubular Myopathy

I have Myotubular Myopathy and, like others I imagine, I suffer fluctuating bouts of depression. The latest one even wandered into existential nihilism for a bit. My main problem is that, no matter how hard I try, cannot see past my disability. Others see the good in me, but I can’t. All I see in myself is my disability and my limitations, not any positives. Does anyone have any advice on how to see past my disability and overcome this depression-spawned mental wall?