Dog of 6 years attacked me for no reason.

Hey y’all, so my oldest dog we have had for almost 6 years now. (Pitbull Great dane mix.) He has never attacked anybody, and has always been my best friend, along with my sons. At about 4:30 in the morning i got up to go to the kitchen for a drink, and our dog was asleep in our bed like he always is.. after finishing my drink i walked back in our room to go back to bed and as soon as i opened our door he started barking at me and then ran up on me and jumped on me and wouldn’t get off of me. my husband ended up waking up and pulled him off of me. He didn’t end up biting me, but even just what he did scared me a lot. (he’s a big dog, and i’m pregnant) He’s never done anything like that before, and it was like he had no idea who i was, he didn’t even try smelling me or listening to me when i said his name and stuff. So help please advice or similar experiences would be awesome. Thanks