Just over 6 months on from starting Couch to 5K I have now lost over a stone and half! Starting at 14.5st (significantly overweight, probably obese) back in September I remember struggling with those first few weeks - doing 5 minutes of running was rather daunting! But I kept pushing myself through it and the stamina to run 30 mins straight soon arrived. Now I am running 3 times a week, I can run over an hour and I am signed up for two 10k races this year.
No massive changes in diet by the way... just far fewer biscuits and crisps. It helps that my wife started Slimming World in January but the weight was already falling off even before that. I still have a few drinks on Friday and Saturday nights but now I'm much more conscious of not wanting to be hungover on a run so I have definitely tempered the drinking a bit.
Anyway, if you're having doubts about the programme, don't! It's entirely achievable - keep pushing and hopefully you'll catch the running bug as I did!