Late with UC50

I am late returning my UC50. I have asked for another time extension but they already did that once, and won't see my request until it's already late (due tomorrow Monday). Does this automatically mean my UC claim has to start again and I've lost all these weeks? I've been receiving £26/month since I started my claim.

Part of the delay has been tech problem on their side but mostly I've been making mistakes and have too much else on my plate and am not well enough to handle the admin project of applying for benefits. Some of my overload is that I'm dealing with Social Care as well and that's taken more energy and time than it's saved me.

I've kept them up to date almost daily with my attempts, and they seem to believe that I'm not making excuses but really doing my best. It's been a perfect storm of perfect storms: tech/internet, money, prescription meds, other deadlines and last-minute panics, adjusting to a new insulin pump which was badly mishandled by the team so I had no training... And various other life stuff that couldn't wait. And I'm pushing myself too hard. Life is chaos on all sides. I'm working to exhaustion every day just to keep myself fed and dressed which is making me less and less well...
I'm pushing myself to meet deadlines and seriously feel I'm pushing myself into another health crisis which I HAVEN'T GOT TIME FOR!

I thought I'd fill it in without being too careful and rely on getting it right at the appeal stage, as I'm assuming I'll have to go to tribunal, that's pretty much a given. I thought I'd quickly go through it to send in, so at least I've done this step, but it wants med reports etc which I can't find and download in one day. Tbh I couldn't have got them together in the last few weeks either, what with everything.