Hi Kazz and welcome,
I was diagnosed about 18 months ago but no-one told me to quit smoking as I also have severe depression so they didn't really tell me much at all.
It was only after my last 'flare up' in February that I felt so bad that I decided for myself that I needed to stop smoking so I quit for National No Smoking Day 13th March, I lasted 30 hours but had some cigs in the house so ended up smoking them after breaking two teeth off and losing my bridge in the process. I couldn't NOT smoke knowing I had to go to the dentist to get the roots pulled!
I promised myself that as soon as I'd been to the dentist that I'd quit the very next day (20th March). I did with the help of an e-cigarette and mini lozenges and have only had one 'slip up' over this past weekend as I had a rough patch of depression...now corrected by my key worker.
You need more info. to know what stage you're at, your FEV1/FVC% etc. and even then there are people who are categorised as 'mild' who suffer more than those who are 'severe'. A lot of it is getting your head around it and controlling it rather than it controlling you (as someone told me).
The sooner you stop smoking the sooner you'll reap the rewards. By day 5 I could breath a lot easier and had stopped wheezing completely. I'm also sleeping a lot better.
Your GP can give you things to help you quit smoking...a lot of people have taken Champix and say that it's really good.
I do wish they (GPs) would give out COPD leaflets to people who've just been diagnosed as its a lot to take in at the time and almost everyone comes away with tons of questions. Make a list of the things you want to know and go back to the GP...it's well worth it but take no notice of time limits on your life - they can't possibly say accurately and it's just scare tactics.
(((Hugs))) and good luck,