Am I disabled with fluctuating symptoms?

Hi all.

So, I have a question about defining disability. Particularly with conditions that have symptoms that can wax and wane.

I was injured at work 18 months ago, and recently diagnosed with Complex Regional Pain Syndrome in my left hand, arm and shoulder. My symptoms can vary immensely, from just constant pain, limb weakness and contracture of my 4th & 5th digits, to spasms, tremors and paralysis of my hand. One flare up to the nerve root even affected my ability to walk. It was 12 weeks before I was confidently back on my feet. Sometimes my hand is almost fully functional for light tasks, but it can also become paralysed in the time it takes to walk to the shop.

I feel like a bit of fraud to define myself as disabled, but also really vulnerable in terms of being able-bodied. 

I'd appreciate hearing your thoughts on the subject.Thanks for reading. ?