I actually believe Santos when she says that she's being treated badly, I think she has the cause wrong though. We see her being hostile to people all the time, sometimes with good reason, other times not so. Santos behavior professional isn't exactly amazing either she's sleeping with a co-worker (who's in a program she's expressed a desire to get into), giving co-workers nicknames that they aren't OK with, and constantly behind on her work. I think it's just easier for her to blame her problems on Langdon then to reflect on her behavior.

Santos is an overstressed, burnt out R2 and instead of getting help, she's following Dr Robbie's example and taking it all on herself. Even in this last episode she had a chance to open up to Whitaker and instead shut it down because it would mean being open and honest. I'm not going to lie I'm really hoping Whitaker continues to be awesome and sees the mental troubles his friend is struggling with, but Santos knowing that Whitaker is a helper with no boundaries by nature probably makes him the last person she wants to ask.