Just how valid is the concept of IQ? Throughout my life I've always thought of myself as borderline retarded/average at best, but recent psychological examination that was part of my depression screening revealed that I have autism and and an IQ of 130+, which supposedly means I'm more intelligent than 98% of the population.

I'm very inclined to believe that the tests are utter bullshit cause if the score had any validity I wouldn't be constantly struggling with learning new things, missing simple details even when I'm attentive and having extreme difficulty with things that require common sense (I get that this isn't strictly tied to intelligence but still, feel like my stupidity definitely plays a big part in this)

Can someone more educated on this shed some light here?