So I will update you on SSDI/Cobra/Medicare (cautionary tale)
Sorry for doing a second thread, but... tough. If you can deal with cancer, you can deal with a second thread. 
So, what happened is that I originally went on SSDI about 6 years ago, but put it on hold when I was able to return to work. Nevertheless, because I had the longer SSDI window of 7 years, I remained "qualified" even though I wasn't actually using it.
I left that employer after a few years (laid off, company is changing). They gave me severance and health coverage for 6 months afterward though, trying to be nice since I'd been with the company since early on. I appreciated it very much.
I ended up working for another employer - and coverage - in time so I had no break in coverage (new insurance kicked in the day after the old one expired, which is great) - until I left recently (that company was highly dysfunctional).
I left my last "employer-insured job" two few months ago (just taking a break and doing contract work since). I applied for ACA, figuring I could get insurance during the special enrollment period, which allows it for certain circumstances (like losing employer coverage).
I wasn't eligible because I was "eligible for Medicare", so I figured I'll have to sign up for Medicare.
What I found out, though, and this may help someone, is that although I am "eligible" for Medicare, I can't get it until the regular enrollment period takes effect - next July - and I can't get ACA because I'm eligible for Medicare. In other words, I can't get either, I think. Apparently I'm automatically enrolled in Medicare A, as a result of SSDI, which covers inpatient, so if I end up in the hospital, I'm okay, but doctor visits, any tests, other required things (like flushing my port) and prescriptions (particularly!) are not. I might be able to wing it out of pocket with the doctor, but likely cannot go into next summer without prescriptions (although I'm trying to get everything into generics, even if they're not optimal, otherwise I simply couldn't afford the multi-thousand dollar/month cost).
Ah, so, the question is, why can't I get into the Special Enrollment Period? I did recently lose employer coverage, after all.
When my former company was being nice and giving me coverage, it was officially through COBRA. They picked up the COBRA payments for that six months. Very nice. However, in the eyes of Social Security, that's a gap in employer coverage. COBRA doesn't count. Apparently COBRA is secondary to Medicare and in their eyes, I had a gap in coverage and aren't eligible. As far as I'm concerned, I kept coverage (paid by employers) all this time, and didn't ask to tap into the Social Security system until I had to. I thought that was the "American Ideal" and to use a safety net like Medicare only when other options are expired. I thought it was good that I wasn't tapping Medicare. Isn't that even what the Republicans want? I was trying not to use the government until necessary (despite the fact that I paid a lot into the system over the years).
Apparently not. You are not rewarded for doing so. I guess the takeaway cautionary tale is if you're eligible for SSDI (even if you're not collecting because you're actively working) don't go on COBRA, regardless of who pays for it, if you think you are going back to work. Only official employer coverage counts. Counter-intuitive, but that's the way it is.
Like I said, I thought I was (1) doing the right thing and (2) didn't need it because I was covered. As a result, I'm screwed.
This is my first trip through the Medicare system. Just in case anyone finds themselves in a similar situation, be aware that being on COBRA, even for a month, totally screws your ability to get into Medicare in a Special Enrollment Period. FYI.
= new reply since forum marked as read
and it was lost with a keystroke 
Bottom line, our system needs to change, we need to reward those who are willing to take a chance and those who would like to be more productive within the SSDI system. Instead we are left picking between the known envelope and what is behind door number one, two, three. Those who have already qualified for SSDI, my husband was approved after three weeks, and who venture out should have a backstop without going to the back of the line.
This is a subject worthy of more discussion, thanks for sharing!
"and it was lost with a keystroke"
Well, we all need to embrace change, if only from our computers. 
The other thing you mentioned: "
those) who venture out should have a backstop without going to the back of the line. " is it exactly, and you see this with unemployment benefits too, though I haven't had those for a few years, thankfully. But in my case, forgetting money and just focusing on the insurance issue, I got a formal job and stopped SSDI payments. After a few years they restructured and laid me off but insurance was kept running through COBRA and I got another job shortly with no lapse in coverage. I should be able to get into the special enrollment period (lost employer-paid coverage) for ACA, but I can't because I qualify for Medicare because of SSDI even though I wasn't receiving either at the time. But because I was technically, apparently, eligible, for Medicare, I'm disqualified from the special enrollment period, even though I was trying to keep myself off the government books. WTF?
that is totally wrong IMHO!
Why even try to supplement your income?
" I should be able to get into the special enrollment period (lost employer-paid coverage) for ACA, but I can't because I qualify for Medicare because of SSDI even though I wasn't receiving either at the time. But because I was technically, apparently, eligible, for Medicare, I'm disqualified from the special enrollment period, even though I was trying to keep myself off the government books. WTF?"
Than for alerting us to how they system works.