Newly Diagnosed and low IQ

Hi, i'm a 34 year old female recently diagnosed with Autism from Belgium. 

It wasn't big news to hear i'm on the spectrum because i kinda knew already that this was the case since longer and i have a brother who is on the spectrum as well, and probably my father too who is undiagnosed. 

I always refused to get myself tested because i was a happy and bright girl and tried to be independent like my peers but it was always with a mask on and great difficulties. Everything is a struggle, from going to bed at night on time (always slept very late) to being anxious about new situations and change, scared what other people may think of me in social situations, getting dressed on time and what to wear, getting out of the house is a big struggle, crossing the streets etc... 

And yet, i'm a very clever woman, i like philosophical topics, i like to act and perform on stage, i like music and good at it, writing and so on, i have manners and etiquette and i have a good eye for detail and good taste for furniture and clothes. I'm very good in speech and communication, and always know what to say to people in certain situations even offer help, in short, most of my friends and people i know see me as a very intelligent person and YET, i scored 65 on the IQ test they offered me during my testing which is extremely low. I always knew i had learning difficulties and that i'm slow in picking up things but that my IQ would be so low, is a slap in the face...I am desperate for answers and people in my environment are shocked by this result. The place where i took the test called me mentally weak (don't want to use the R word) They told me its due to my autism, that my autism is bringing down my intelligence (in the moment) I can relate to that cause when i did the IQ test i was often nervous and had a hard time focussing on things. So it surely pushes down my intelligence but i don't want to be on par with people who have mental weaknesses such as people with let's say Down Syndrome, although i think those people are amazing and lovely people. But i'm so confused because you would never guess i have such a low IQ on hearing me talk and meeting me. Most people are even shocked i have Autism cause i blend in well with other people. I do tend to have a unique look on life and i'm very compassionate but that graces me.

So i'm wondering what those IQ tests actually mean on people with autism and i'm thinking the worst now, and i have been crying since then. Feeling so worthless and small now. But it's probably very different from other people with mental challenges. I don't know, can someone tell me more?

Thanks so much!