My son (who's also 3) went through a total night terrors phase. It totally freaked me out and I had no idea what to do, he'd flail all his limbs violently if I tried to hold him. I eventually learned (after a lot of trial and error) that I had to kind of tackle him into a hug and just hold him tight even though he fought and then he'd calm down. It wasn't the exact same as what your talking about, but I had that same sense of confusion and hopelessness over it.
I'd guess your DS is maybe just freaked out because he woke up in a weird place (assuming he doesn't often curl up on the couch for a nap).
I don't really have a suggestion for you, but wanted to just say I've dealt with some weird sleep stuff too, which he's now outgrown, and your not alone.
I hope he calms down okay soon.