Is the only pre-req to being disabled having a disabling condition? Or does it have to be to a certian extent? I'm asking not because I want discource but because I have migranes and I don't know if I'd actually be welcome in the community or to get a flag
No worries. This is actually a good question.
The short answer is: "Disability is much like being Queer; if you find yourself asking: 'Am I really?' the answer is probably 'Yes!'"
Here's the longer answer, from the U.S. Government's official website about the ADA (Americans with Disabilities Act) -- I added the bold emphasis:
To be protected by the ADA, one must have a disability, which is defined by the ADA as a physical or mental impairment that substantially limits one or more major life activities, a person who has a history or record of such an impairment, or a person who is perceived by others as having such an impairment. The ADA does not specifically name all of the impairments that are covered.
So if your migraines limit your activities (mine do), then yes. You're a member of the Disability community.
Those other clauses in that definition are important, too.
So if you were once disabled, and have recovered, or if your disability goes through cycles of remittance and recurring, you still legally count as disabled, even if your condition is not limiting you today.
And if you have a condition that does not limit your life activities, except that people react to you as if you're disabled (say for example, you have a facial deformity, or vitiligo, and people treat you weird, or be reluctant to hire you), than that counts as a disability (under the ADA), too.