I have been diagnosed with anxiety but it's getting so bad that i can't fall asleep and i'm up for 18-20a hours and only sleep for 4-6 is this bad?

Could be a problem: People's needs for rest and sleep certainly vary. Some say they feel fine with only 4-6 hours of sleep a night, but you indicate you "can't" fall asleep . . . So it sounds like you're not pleased with your situation. Anxiety can cause insomnia, and so can some other problems. I hope you'll consider seeing a psychiatrist for a full evaluation, so that you can receive effective help.