So I told my line manager and he was really nice. It's a relief to be honest. He said I didn't have to tell him, but I said at this point in the situation I felt it best to be open rather than make something up explaining my absence given we work so closely together (which I think he sort of agreed with).
He listened to all my worries about the bosses discriminating and tried to reassure me that he has my back (and he won't tell them of course). He asked if he could give them any more info if they asked a direct question and I said absolutely not I don't trust them. But I think he appreciated that I trusted him enough to tell him.
I was upfront about my (would have been) Mat leave plans which he said not to worry about and they'd manage whatever I wanted to do, but I'm glad I managed to tell him that I had had a plan and i was never going to just leave the team in the lurch.
Also picked up my mat clothes sleepsuits and baby sling from the jojomamanbebe delivery. I didn't feel upset. I just hope I get a chance to be pregnant successfully again in the near future.
Physically the bleeding has thickened but it's still not constant. They told me that the cervix is still quite closed so it may not happen before the surgery on Wednesday, but it could. That's why I can't risk going into work.
Sorry for the essay it's helpful to write on here.