Too unfit for couch to 5k...

Have you got an android phone? I've got a "walking for weight loss" app by redrock apps that works in the same way, split over 6 weeks but is designed for "those that have been on the couch longer than others". It starts you walking and you build up to a jog, then you start the couch to 5k. I'm 21st+ and only done week 1 so far but it really isn't bad.

When I started I couldn't jog for 60 seconds without tasting blood!

It's took me 3 weeks to complete week 1. It took me 6 weeks to get to week 3. But I keep going and it gets easier
Good luck!!!

You says it's hard, but how much did you manage?
Can you walk for 40 mins (the 30 mins it wants you to end up running, plus warm and cooling times)? If you can walk for 40 mins, you CAN do this.
Try to do the first session again, but run really slowly, and walk one or two running sections if needed.
If walking for 40 mins sounds impossible right now, try and build up to that before C25k

Well done you on starting the journey .

The hardest part of couch to 5k is getting off the couch so just get used to doing that first.
If you are starting from zero then just make the commitment to go for a walk for 20 mins (or however long you like) 3 times a week. It doesn't matter how far or how long but just get yourself in the routine of doing something regularly. Once the habit is formed (ie the hard bit) then you can just change what you're doing and start the C25k, or anything else.

A running club near me has actually set up regular walking sessions to get people off the couch as a precursor to their C25k sessions for this very reason. If you're in the NE of England OP let me know and I will PM you the details.

Stick in! The journey of 1000 miles 5k starts with a single step

It's OK if you need to run some of the walking bits, just run as much as you can, you'll get better.
Have you considered cycling instead of or as well as running? I find it much easier and it'll build up your general fitness levels which will help towards running

Can you join a group of beginner runners? Bit more motivation if there are a few of you.

If you are struggling with the run sections then do the whole program as a slow/fast walk program rather than a run/walk program. Once you've upped your fitness a bit then do it all again as a run/walk program.

Well done for getting out and doing something.

Did you manage the first session though? If you did, then you are doing fantastically, and remember you've made the biggest change already.

Nothing wrong with doing each week twice, and make sure you run really, really, slowly

Have you just the first day? Could you keep repeating it until you improve then move onto day 2 and so on. Or fast walk the running bits?
I know what you mean, I'm on week 5, but it's taken me a lot longer than that to get there. I repeat a run until I can do it.

Maybe the simplest option is to take literally the old adage 'don't run before you can walk' and start by getting up to 5k fast walking by alternating walking as fast as you can with slower sections?

I suspect you need to slow it down a bit. I completed C25k at 23 - 21 stone (lost while doing it). ]

You dont have to sprint the run sections