Hello and welcome.
First of all, well done on being brave enough to admit to yourself that your weight is affecting your health and that it is scary. You've made a big step in acknowledging it and deciding to do something about it. It was being worried about my health that lead to me joining Slimming World 5 weeks ago and now I feel more positive that I am doing something about it. I hope you will be able to feel the same way soon.
Secondly - very well done on stopping smoking, even if it is for 3 days so far.
That is hard to do and you should be proud of yourself. I've never smoked but everyone in my family did when I was a child, so I have seen people close at hand suffering with the health issues and the difficulties of trying to give up. My father died at 50 through smoking and it was a contributing factor in my brother's death last year. I'm sorry if that sounds like I'm trying to scare you some more - I don't mean to,but if you can stick with giving up it will make a huge difference to your health. My husband smoked long before I knew him and gave up 30 years ago - he very quickly saw the benefits, in months not years. He is now very healthy and exercises every day. If you stop smoking the effects of it can be reversed, so there is a really good reason to stick with it and be proud of yourself for getting even to 3 days. If you start to struggle then there is advice on the internet and your doctor might be able to help get you some support. Don't forget that when things get hard - it is not you that is a failure. Smoking is addictive, in habit and chemically - cigarettes are designed that way. So don't allow yourself to feel bad about yourself if you struggle at times.
You say that you are depressed which is very sad to hear, and I would recommend speaking to your doctor about it if you haven't already. The fact that you eat when you are feeling very low is something I think you should consider when deciding what type of diet / plan you are going to follow. Hopefully other people on here will be able to advise you on the plans they are following. It is worth some time researching and thinking about what suits the way you use food, your eating patterns and of course your budget. You might find a plan with a weekly meeting helps with an extra bit of support.
The only one I know a bit about is Slimming World. One of the advantages of it is that there are some foods that you can eat as much as you want of, so you don't have to go hungry (I get really cross and irritable when I'm too hungry!). If you plan your meals and snacks out in advance on it then there will always be something you can eat without feeling bad about it. There are also allowances for treats so you don't have to give up on everything you enjoy. I would recommend you take a serious look at slimming world and see if it is right for you. There are lots of local groups around the country so if you can get to one that could be a good thing to do - it will get you out for 1.5 hours a week with other people who are also trying to lose weight. The idea of planning your meals in advance might seem like too much at the start, especially as you are battling with depression, but it gets easier and there is lots of help and advice on the internet and here on the forum. There are also some quick meal and snack options that can make it easier.
Also I am finding it helpful to have a target to work towards, but it is important for me personally that it is a realistic target, otherwise I am prone to telling myself it isn't achievable and giving up. Have a think about your own personality. Will a very ambitious target spur you on, or like me, make you more likely to throw in the towel. Would having so interim targets help? You know yourself best so think about what works for you. We are all different and won't always find the same techniques helpful.
I also found reading stories of other people who had lost weight to be helpful. There are lots around and they can be good reminders of why you are trying to lose weight and the benefits of doing so.
Congratulations on getting out every day - just walking is a great way to get fitter. The longer you are not smoking the more you will notice the difference. You will find yourself breathing a bit easier. You may even be able to start increasing your pace or distance a few months from now. When I have had depression in the past I did find getting out for walks to be a great help.
You have been very brave coming on here and you clearly want to improve your health. The last bit of advice I have you you is - don't be too hard on yourself. You are trying to do a lot with giving up smoking and trying to lose weight. Accept that there will be sometimes when things don't go as well as you hoped. This is inevitable and you need to remind yourself that it doesn't mean you should give up, or that it reflects on you as a person. It happens to us all, even the successful slimmers.
I seem to have gone on a bit here - I am no expert and have only given advice because you asked for it. Please ignore any or all of it! I wish you the very best of luck.
Take care
Denise xx