I am concerned but I am also telling myself that in reality I should be no more concerned that I was two days ago. The US could have/could change(d) the entry requirements at any time. If I have to have a PCR test before I fly to the US I will, but if I have to quarantine in the US for any period on arrival then I will cancel.
There will be some cost implications if a PCR test is required and also some if I cancel, eg. Kennels deposit. My daughter and I have unactivated APs for WDW and UOR, which will just be held in the system. My son has a 14 day WDW ticket purchased from Disney (but that will just stay in the WDW system) and yesterday

I bought a 14 day UOR ticket for him from UOR (again I think UOR will just let it sit in the system). And yesterday I took advantage of some Black Friday restaurant offers. So it seems it may be more about money being tied up, rather than lost. We have a decent LV family annual travel policy as a back up.
My daughter and I have another trip booked for March. My biggest problem I think, because my daughter works at a boarding school, is trying to use up any BA vouchers that are issued before their deadline, which I think is September 2022.
Also, I have now missed all the Christmas supermarket delivery slots and I hate shopping at Christmas. Oh, and we have no Christmas presents to exchange as we agreed to buy each other token gifts at the parks.

Edited to add no Christmas tree ordered, no turkey ordered ….. .