How do I fall asleep?! I can't!!?

I'm sooooooo tired but my depression and anxiety has kept me awake for the past three days (minus a few hours here and there). I mean I have always had problems falling asleep and staying asleep but it's getting worse. And I can't just keep NOT sleeping and I'm so exhausted and cranky and I just CANT SLEEP!! I mean I've tried EVERYTHING!! I've tried the hypnosis videos and the whisper videos on YouTube, the "white noise" downloads on Rhapsody, the sleeping meds (but they give me screaming headaches all the next day), reading, drinking tea, cuddling with my dog, taking warm baths, and even takin a few benadryll to knock me out but NOTHING WORKS ANYMORE!!!! helpppppp meeeeeeeeeeee!!!! :c