I started my SSDI application in December 2016 but finished it in February before submitting it. I kept going back in and it said "processing". Today I decided to call my local SS office. The person I spoke to said it had been approved (!) but she wasn't sure why there had not been any payments yet. So she put me on hold a couple of times, said she was emailing the person who worked on it and said I should get a letter in 7-10 business days. It was approved effective Dec. 2016. So if you are waiting, and checking online, CALL THEM! I have been worrying about this for months, and running low on money in my checking account. I won't be making that much but it will certainly help, and it will only be 6-7 months of back pay. I feel like a weight is off my chest today.