I tested with a first response this morning (goodbye, $12) and got a very faint BFP that showed up after 3 minutes but still before 5 minutes so I don't think it was an evap line. Cautiously optimistic and hoping for a sticky bean. I'll test again in a couple days, or I might ask for a blood draw tomorrow since I have a doctor's appointment anyway.
(I guess I should've been in the January 2WW thread, lol)