It could be a water issue. How often and for how long do you water? Have you tested the soil moisture at depth?

There is also the possibility of clematis wilt. That typically starts first at the top of the vine and progresses downward. Was that a pattern you saw?

Oh my gosh, yes, the wilt started at the top and moved down to the bottom. Also, my husband and I each unknowingly watered it two days ago possibly overwatering it, but it sounds like wilt given the pattern it progressed. What can I do if it is Clematis wilt?

If it doesn't perk up or it starts looking worse, then cut it back hard. Keep on watering as needed. The problem is almost never fatal but you may or may not see any clean regrowth this season. Even if you do not, it will very likely resume growth next spring as if nothing had happened.

Thank you so much.