Why get diagnosed? For another patch on the vest of diagnoses? Just self-diagnose. Not like they have pills to adjust dyslexia that would require a diagnosis to prescribe. Not like it is a mental illness or anything - it's a learning disorder (or an info processing disorder, something like that). You don't need a doctor to figure out you have a learning disorder or info disorder.
I had to add an edit to say that I have dyslexia too, just a teeny bit. If it is not bad enough that someone reading your work notices, I don't think it is worth an official diagnosis.