I’m just generally and genuinely unintelligent and it’s making my life hard.

I want to know if anyone has any advice or any thoughts they can offer me on this. I’m pretty self aware of it but I know for a fact that I am unintelligent, and I don’t try to fool others into thinking otherwise. I’m just socially, intellectually, and academically stupid. I really don’t know what to do or how I even got into the uni I’m going to but slowly but surely every single person I meet just admits or makes a comment eventually about my unintelligence (not in a mean way trust) and honestly I don’t get offended by it. Why get offended by facts? Not like denying it or getting angry about it will make it untrue. I have ADHD and I was always in the “behind/special Ed/whatever (I’m not sure what the correct term would be) classes growing up and during my recent ADHD diagnostic test, they did confirm that I was for no better term “slow”. Not saying that ADHD is the reason or cause or that people with it are unintelligent, it’s just something extra that I struggle with too. I struggle socially and academically and I’ve been having some pretty dark thoughts. I was born very lucky and I study abroad at a very good university but every day I keep thinking that they got the wrong person. Why did this dumbass get these awesome parents and these awesome opportunities? My parents should have paid to send another kid to uni, not this stupid NPC. I’m so grateful and it’s so beautiful here but I’m struggling. At all times I feel like Joe Dirt the Ragman was just dropped in the middle of a conversation between Einstein and Steven Hawking pretty much during each lecture and every social interaction I have. I’ve been declining socially because of this and in order to cope with my unintelligence I’ve just decided staying quiet is easier so at least I can fly but this super sweet and nice quiet girl persona, even though I truly do want to be more talkative and outgoing. It’s just hard when every time I open my mouth only nonsense comes out. I just can’t think. Thinking is so hard for me. When I think about thinking I think about thinking and then I’m not actually thinking. Does that make sense? I get so caught up in it. I’m lost. Help…