Not an R.
This got a 12A but the MPAA as per usual can't seem to rise to the same level of maturity. The official reason was, "depiction of strong thematic material", which is blatantly code for "Semi-violent action films are okay, but we really hate abortion."
For the relatively small amount of teens interested in seeing a low key drama with provocative material in it, a PG-13 would encourage them to do so.
"How am I supposed to heal if I can't feel time?"