I'm starting to think that my life is over and I don't want to live anymore. As of writing this I am a 23 year old woman with no qualifications or education. I have learning disabilities and my IQ is just 76. I struggle with things like talking, maths and spelling and I can't find a job.
When I was a kid I knew I was different. Things that were easy for the other kids to do took me ages to learn. Kids used to make fun of me because of the way I talked and in general I could fit in. As I got older my learning disabilities become more noticeable. I was diagnosed with ADHD and low intelligence and therefore struggled academically but my dad refused to put me in a special education program because he thought it would be an embarrassment. School was very hard for me. I would work my ass off just to get C's and B's and my father was very abusive. He would expect me to do well in school and if I didn't he would beat and punish me. I had to repeat the 7th and 9th grade but I eventually graduated but very poor grades and no qualifications. When I was around 15-18 started to do drugs like weed and alcohol just to cope.
I left my parents house when I was 19 and went to live with a friend. I have very little money as I'm addicted to drugs and my lack of education makes getting a job practically impossible. I don't see my life going anywhere and when I'm not on drugs I'm miserable. My brothers and sisters have done so much better then me and it makes me so jealous, angry and ashamed. I know this may sound cringe but I honestly can't do this anymore.
EDIT: I now have a job at Burger King as a cook. It's not glamorous but it's some money.
TL;DR: Skip to the last paragraph.
So, I studied psychology in university and this is to the best of my knowledge.
IQ is basically scientifically outdated and based in racism and classism. The guy who popularized IQ testing in the US, Lewis Terman, was a horrible racist who loved using it to prove White people were superior to black people. There are much newer theories of intelligence that view it more as a domain-based thing (e.g. someone might not be musically intelligent, but they might be mathematically intelligent and so on).
There are also different ways your score could've been thrown off, too, especially if your ADHD is relatively severe. Unless you have some sort of developmental disability like Down syndrome, it's actually pretty likely your IQ is roughly the same as your siblings'.
Honestly, the real issue here is the ADHD. Take it from someone who also has it: if left unchecked, it can be a life-ruiner. I was a B and C student and had no clue why until I was almost 23 and finally got diagnosed. I got into university, but it was only after spending 4 years in community college. The guy who diagnosed me said that he doesn't know how I actually managed to do it. He said it was like I had been trying to swim with cement blocks tied to my feet.
Forget intelligence for a second. You are very obviously an capable person. You worked hard in school, you have a good command of the English language, and you're holding down a job in fast food (a field that sent me to tears multiple times, mind you). Your problem is that you've had a very rough life with little support. Prioritize kicking your addictions (maybe try and find a recovery group). See a therapist to talk through your father's abuse. See a psychiatrist to talk about medication for ADHD (non-narcotic, of course). You deserve to be satisfied with your life, and I believe you can get there.