Sorry things are going so rough for you right now. Maybe you should get rid of the sugary foods in your house until things settle down a bit. Your son needs you & if you end up in a diabetic coma (or worse) the only people who benefit are your obnoxious neighbors. And they shouldn't get to have any say over your life.
I am a bit concerned about whether you might be borderline suicidal, but I will assume you are just under a lot of stress. I think putting up the curtains & paintings was a really good idea. Yes, you do have every right to look out your window, but no need to add fuel to the fire. If that helps settle things down so you can live in peace, it seems like a reasonable solution.
If you continue to be under a lot of stress, I really would encourage you to talk to a professional counselor. Not because I think anything is wrong with you, just because you have so much to deal with in your life. Autistic children are truly beautiful, but they can be more than a handful at times. Add to that your health condition & your feuding neighbor & it's no wonder you can barely sleep. Having someone to talk to, who's on your side & who can help you figure out how to lessen some of the stress can be very helpful. :)
In the meantime, please take good care of yourself. Get rid of anything that could be used to harm yourself (that includes M&M's) and try to make healthy choices, even if they are hard to make. I am sure you are a wonderful person; you're just going through a really rough time right now. I can relate to that, but even though it feels like things just keep getting worse & there's no end in sight, things do actually get better after a year or so. So, hang in there.
And know you can post here anytime. The people here are HW are really wonderful & supportive people.