I've always been told I can continue doing what I used to do as far as physical activity goes. My advice is listen to what your body tells you and you'll be fine.
My dr has always told me to take it easy for the first 3 months. To not overdo excercise and try and stay stress free. I believe you can never be to to safe so I would just take it easy for awhile. Every pregnancy is different.
I second Kimejo. As long as you aren't hurting, you're probably fine.
I am on #4 and I've run, jogged, worked out, lifted kids, over 25 lbs etc. as long as you are healthy and not being dumb abt the things you are doing you will be fine. Your doc will tell you not to lift over 25lbs if u can help it. But sometimes you have to do what you have to do.
I'd switch to jogging, and you shouldn't be lifting anything over 25 lbs