Hi and welcome. I was like you. Sat in the car after diagnosis and shook with rage and tears so much the car looked like the trotters van after winning the millions!!!
Now 4 months on I am almost 3.5 stone lighter, now enjoy the gym and seem to be getting my BS readings very much under control. If I tell you that I had been trying to lose weight for 20 years or so and kept failing everytime I got to around 2 stone- you may be familiar with this. Once diagnosed it seems to take the pressure off - its not your choice to keep putting it on again, you have to get the weight off to keep your bs good - not to mention having to face the gp more regularly.
One important thing though Peter, and I think Am already mentioned this...first take a big deep breath. Then start gently, cutting down/replacing food slowly and increasing your exercise daily. Don't try and do it all in one go ..you have as long as you need..
Also have a look at the Weight Loss Group forum on here, you will see there are lots of us on the weight loss journey, feel free to join us by pledging a small target loss initially.
Good luck and ask away if not sure.