This has happened to me more times than not with planting hellebores, especially when a warm spell sneaks up on me. The best luck I have had is with tiny seedlings; larger plant often flag on me like this for awhile, and a lot did this spring after I did a huge new planting and the temperatures soared right after. They have so much leaf mass (large, thick, plentiful) to keep hydrated and the root disturbance seems to throw them. They will spend their time settling in and rooting well, and suddenly come out of it…so long as you don’t let them go crispy and dry. It’s not you!