Samaritans aren't the only mental health helpline. Have you googled "mental health helpline"? Best if you do it rather than us as you'll also get ones local to you not just the national ones.
I can't give you an entirely positive story of my own as I'm currently housebound with my own MH issues and really struggling but I've had periods of wellness over the last 10+ years since I became most unwell
But I've friends who've overcome serious depression, are managing bipolar, depression, social anxiety, health anxiety etc there are positive stories out there. There might be some on the mind website?
Re meds feel free to tell us what you've tried and what your experience of them has been we might be able to make suggestions of better/other meds to try?
Sounds trite but a phrase I depend on is
"This too shall pass" no feeling lasts forever, I've had it drummed into me that the body simply can't sustain the long term chemical production of hormones etc to maintain one feeling long term. Even if you're "not feeling completely shit" moments are few and far between at the moment try and note when they happen so you van remind yourself when you are feeling completely shit that even eg this week you weren't feeling like that ALL the time - a reminder of the light at the end of the tunnel which I know at times can feel like the tiniest pin prick but it's still there.
You ARE loved and wanted and you sound a kind thoughtful person.
When you call gp surgery next time tell them it IS urgent (because it is, just because it's MH doesn't mean it isn't, I've had to learn that one myself - following a "ticking off" from GP for accepting not being able to get an appointment as I felt guilty classing it as urgent.) if they're arses about it ask to speak to practice manager and be honest and tell them you were on verge of going to a&e you were that bad!
Unfortunately with cuts etc we are having to shout louder than ever to be heard. Be very clear "I am VERY unwell and I NEED HELP NOW"
Do not hesitate to go to a&e if you become any worse.