Your manager, is this uncharacteristic of him? I mean, has he ever pulled this sort of behavior on you before? What bout your co-worker, is this uncharacteristic of him?
Basically, my advice is to calm yourself. Take some deep breaths. Then go have a gentle conversation. For example:
To your manager: call him on the phone. Talk to him calmly and without anger. Say, hey, I've noticed a change in your behavior towards me that is uncharacteristic of a person with such integrity as you. I mean, I know you, and I know you to be a understanding, professional person. Can you share with me what's on your mind? and then the most important part... listen listen listen.
To your coworker: go to him directly with what he wrote. And ask him, hey, I noticed this and I was told you said this. Can you tell me more about this? Have I done something to earn these comments about me?
And of course... listen listen listen.
All this is provided that you do trust them and that you do have a good relationship with them - meaning, all this stuff is new and started out of no where. If there is some merit to what they are saying about you, own up to it. such as: to your manager: I know I have not been as available to you as much as you would like, and I apologize for that. I think we can solve this issue together. Maybe we could have weekly scheduled meetings with open agendas, that way, we will have an opportunity to communicate more effectively on a regular basis. etc.
Then again, if they truly are just big jerks that are picking on you because you are pregnant, I'd say, leave. No job is worth your well being.