9 weeks pregnant with twins

I’m currently 9 weeks weeks pregnant with twins. I’m slowly starting to feel better from pretty awful all day nausea so I’m predicting and hoping I’ll feel MUCH better come my second trimester and I want to start going to the gym! I’m not the most athletic person ever, I’ve got some pretty naughty eating habits that I’m working on and I’ve always had some fluff to me but I’ve managed to consistently go to the gym for the last couple years, with a week sometimes month off here and there. I’m not trying to lose weight by any means but I do want to maintain a healthy weight and keep active!

I’m wondering what are some workouts you guys did during your pregnancy other than just walking. I don’t know how to swim otherwise that would be PERFECT! Is it safe to bike? Elliptical and stair master?