How about mustering up some of that helpfulness for yourself?
As someone else mentioned, your friends and family are not equipped to deal with your mental health issues. They are probably at their wits end and have no idea what to do now to help you.
I'm sure they have made suggestions but when someone is terrified of seeking help, what can they do? Short of dropping off food from time to time.
They probably do care, for sure your Son does, he's still in touch but he is probably lost as well.
Mental problems are complicated and again, people don't know how to deal with it. How do you help a family member that won't eat? Actually start there, how would you help them? Help yourself using that same helpful nature you have.
Have you called Meals on Wheels? I don't know your age but you might qualify regardless. If nothing else, can you call them today? If you don't think you can you could perhaps ask your Son to fill out the referral, they take referrals from family members and friends.
Register For Meals | RI Meals
As for the Samaritans from looking at the site it sounds like they are a group that will listen and also they know what resources are available. So a call to chat certainly couldn't hurt, first things first though, perhaps Meals on Wheels is a place to start today.
I understand the fear in calling the Samaritans (I really do) but remember, you are in control, it is just a phone call, you don't have to do anything you don't want to. Find out what your options are, they may offer help that doesn't actually terrify you, so a phone call can't hurt.
What have you got to lose at this point except more miserable days. It does not have to be that way.