Take it easy and just enjoy it at your speed. you can ride almost everything, of course skipping out the bouncy rides and coasters.
I've been to DL while pg twice and both times had a fabulous time.
If possible bring a towel for the parades so you have something to sit on and to "mark" your spot : ) (it's likely you'll have to excuse yourself for the ladies room and want to make sure your space doesn't disappear!)
Also, bring whatver food you need in case you feel ill. (crackers, ginger, etc.)
Congrats!
Jenn