You should read up on the absence/capability procedure at your company. I can understand your being concerned that there is a meeting but remember it's only to consider your record and consider whether action should be taken. It may be that you will be 'informally counselled' or that a medical expert report may be sought. The worst I would expect is an oral warning, but that is usually the first step in a fairly long process.
If you return to work soon and the absence record improves sufficiently the warning may simply expire.
If you stay off or it doesn't improve you may eventually move onto written warnings and final written warnings, but that may be some time off.
Make sure you get a colleague or union rep to attend with you and ask them to argue the point about DDA- the employer should make adjustments and perhaps set different criteria before taking action.
But at the end of the day if your absence continues for months or you regularly have long absences the employer is entitled to dismiss you.