People can still sign up for the ACA in some states, e.g. Minnesota thru January 14

[progree]

for coverage that begins February 1.

I'm pretty sure extended deadlines are true only in states that have set up their own exchanges, about a dozen states, if memory serves me correctly. For states where you use healthcare.gov, it's over I'm pretty sure.

Anyway, if you have a state-run ACA exchange, check for the deadline -- it might be something like Minnesota (mnsure.org) with an extended deadline.

Edited to add: options other than ACA that might work (from BMPM's thread) https://www.healthcare.gov/blog/2019-open-enrollment-ended-see-options/