Hi Johanna, I’m in zone 6 and until about two or three weeks ago most of my clematis looked like dead lifeless twigs and now they’re scrambling all over the place! Keep an eye on the buds, you should start to see some swelling in the coming weeks.
Don’t give up hope too quickly! Sweet Autumn’s a pretty sturdy plant…I’ll bet it’ll be just fine through your rain and snow. Just give it some time to wake up from dormancy.