I feel defeated

I feel defeated because I try so hard to fit in, both socially, and at my work. I feel incompatible with most aspects of life and I'm unsure how to overcome this feeling. When I speak of things I find difficult, people tell me that it's just the nature of life/work, and I feel so deflated by this answer because I'm really trying my best and if this is how I feel at my best then I don't see how to move forward.

Has anyone else gone through this feeling? If so, please share with me any advice you have. I would be so grateful for any recommendations of books, coping techniques, podcasts etc. I'm also finding the lack of adult autism support difficult to cope with. I can't find any helplines or chat support services that are for autistic adults. I feel very isolated and I would prefer to speak to someone who has experience and knowledge of autism, rather than speaking to a non autism focused service such as Mindline. Please let me know if you are aware of any adult autism support helplines in the UK.

Thank you in advance if you have shared any advice with me.