Believe it when it happens.
Oh, if it happens, it's a catastrophe.
But Collins and Murkowski won't vote to defund Planned Parenthood (which the House AHCA does). That leaves 50.
Portman won't vote for anything lowering Ohio's Medicaid expansion (which the House AHCA does). That leaves 49. So they can't even get it through via reconciliation.
Plus there are probably a few other Senators who will feel the heat from their states over the Medicaid cuts, and others who will be afraid of their re-election chances (Heller and Corker come to mind) if the subsidy structure changes.
Plus the Republican Senate leadership said, upon the House passing the AHCA, essentially, "Good job. Now we'll consider our own version (Cassidy-Collins) and get back to you in the conference committee."
EDIT:
In the category of "Things Trump may have normalized":
https://www.youtube.com/watch?v=DeaXDIsch_EGreg Gianforte, Republican candidate for the House of Representatives in Montana's At-Large district in the special election taking place tomorrow (go vote!), has apparently body-slammed a reporter from the Guardian who was asking him for his thoughts on the AHCA now that the CBO report on it has come out. So far there is no video of the incident, only the audio played in the above clip.