Lazy or stupid but altogether hopeless

Im 25 years old. I dont care about anything or anyone. it seems like its been like that most of my life. i feel really guilty but also too lazy to do anything about it. i just want to end my life coz i feel like there’s no future for me- i cant hold down a job coz i cant learn new things/ i cant problem solve or think indepdently or have an opinion about anything for some reason (am i mentally retarded?) and i cant make any meaningful friendships with people. my sister- who is unbelievably patient and supportive of me in my bottomless negativity- is getting married. but instead of feeling happy for her, the anxiety of having to speak at her wedding overpowers me. i really and truly feel like i dont care about anything and that i cannot think for myself. thats what i realized at my last job- i couldnt socialzie with people, i couldnt understand what they were saying to me and i couldnt understand what i was meant to be doing despite it having said to me on numerous occasions. i duno why im writing this in this space, i dont want to take meds or seek therapy- ive had a very untraumatic upbringing…i dont know how im going to overcome this really. i just want to not exist, just want to disappear.