Having seen the aftermath of suicide, I can assure you, whatever you're thinking isn't actually the reality. You are both loved and needed and would leave a huge hole in your children's lives. Your mind is deceiving you.
Can you make an emergency gp appointment tomorrow? Do you have a friend or relative who can advocate for you? Insist on medication or a change of medication if you already have a prescription? You really need to push sometimes and if you aren't up to it, might be useful to have someone bolshy with you.
You can also Google "Crisis Resolution and Home Treatment Team (CRHTT) + your area" and they might be able to offer alternative advise or support. They operate slightly differently by area but should have a 24hr phone line.
Have you tried calling 111? They might be able to direct you to alternative resources.
FYI if you don't feel like talking: You can text "SHOUT" to 85258 for free from all major UK mobile networks. You'll then be connected to a volunteer for an anonymous conversation by text message. This is not an NHS service. This free, confidential, 24/7 text messaging mental health support service is run by a charity called Mental Health Innovations.
If you feel up to it maybe give Samaritans a try. You can always end the call if it's not helping.
In the meantime, can you distract yourself with something menial or mundane? Cleaning the kitchen? Take the bins out? Reading one of the kids story books? Watching dodgy home haircuts on YouTube (Brad Mondo)?
I doubt it's that the people around you don't care. They probably don't understand though. Sorry you're feeling shitty 