You are Severely stupid aren't you.
You capitalized "severely." I assume this is because you didn't know how to spell severely and couldn't find it in the under powered spell check of this chat box. So you typed it into a Word doc which auto capitalized the first letter thinking it was the beginning of a sentence. Then you copy/pasted the word, capitalization and all, back into this box. Or you think "severely" is a proper noun.
Also "aren't you" turns the sentence into a question, requiring a question mark ( ? ) instead of a period ( . ) at the end.