I actually did the same thing yesterday with a new group 2 clematis. I'm just treating it as a hard prune, lol. This is the year for it to work on the root system anyway.

LOL! I keep going outside to hover over it. I'll try to relax and heed your advice, think of it as strengthening those roots. Thanks, neighbor to the North.

This will actually help it and not hurt it at all.

I cut all of mine to 6-12" when I plant them. If they have buds when I buy them, I wait until after they finish flowering.

I accidentally 'snapped' mine off last spring (I had just planted last spring) while weeding around the garden. It came back even better after that! Even the same season! Just keep treating it like nothing happened. Water, water, water. It'll be just fine.