Running while pregnant?

Many of you that are my Facebook followers already know that I'm expecting baby #3 in March, but if not, there you go. I am almost 13 weeks now, and feeling a little better than I did in the first trimester. When I first found out I was pregnant, I was bound and determined to run the entire time, even if it was slowly. Well, that was at 6 weeks when I still felt great. As soon as the exhaustion and morning sickness started, running was the LAST thing on my mind. So all you pregnant/past pregnant runners out there, did you run through all of that or did you wait until you felt better? Right now I feel like I could get a small run/walk in, but by the time I get home at night I'm so tired it's impossible. And forget about waking up early to do it, I barely wake up early enough to get to work! I know all the benefits of exercising while pregnant, and I'm on board with it, I really am. I just need to get my body on board with it as well. Any suggestions from experience would be greatly appreciated! I don't want to gain 100 pounds while I'm pregnant!