Danni, basically to your SIL - you do what you are comfortable with. I'm sure you're not just lying around going "ooh I'm pregnant I can't do a single thing" but at the ohter extreme I'm sure you weren't planning on jetskiing either! Do what you feel comfortable with - if that's just gentle walks, watching what you eat & enjoying every second of it, DO IT! Sadly as soon as you fall pregnant everyone is an expert & you'll be stuk with oodle of unwanted advice like this.