Katherine,
Having moved four times with small children, I'm starting get the hang of it unfortunately. One of my sons was 18 months during one of our moves. The problem was he knew something was going on but was really frustrated with not understanding. He was big enough to know that things were happening but didn't have the vocabulary to tell me he was really angry.
For time outs, it's one minute for every year. Though, at that age, they really don't understand timeouts. It's good for you though. The best thing at that age is to move them from whatever they are doing. If she is throwing a fit over a toy, take her from the toy, go to another room and get her attention shifted to something else. It's tough at times, but it does help. We would move really fast, pick them up (gently yet quickly) and move them to another activity. Most times they would completely forget what they were so mad about and move on.
Unfortunately, you're topping off a move with being pregnant - another change in her life. Kids are adaptable, but anticipating change really is harder than the actual change itself. If it helps, here are a few things that we did at that age:
1) Pack her room last - she's too young to understand that her things will be unpacked once you get to the new house.
2) Have her "help" you decorate with markers a special box or bag that will contain the toys that are most important to her for the move. Then she will know where that box is at all times and know what's in it (It can also be the first thing you unpack).
3) Walk her through the house and show her what you have packed or not packed. She's not going to join the conversation, but I found that our son responded really well to this. Everytime I was going to pack something new, I told him about it and talked to him about where it could go in our new house.
4) I bought a set of Peek-A-Blocks and gave him a new one every morning.
The point to all of it was for me to distract him and keep him from focusing on what we were doing.
I hope this helps in some small way. Congratulations and best of luck!