How can I get my IQ tested?

I’m extremely slow & I’m tired of noticing how annoyed people are by it. At work I didn’t even know which way to scan gift card, I’m practically helpless.
I don’t know why I’m extremely dumb, but I’m just tired of it.
I’m also tired of being unsure about how stupid I am, I feel different from everyone else and I’m starting to think it’s due to intelligence.
I don’t listen to directions well, I don’t remember things, I’m bad with social cues especially sarcasm vs. serious.
People just get used to having to cradle me around because I don’t understand anything.
Is there any fix to this?