Between 1st trimester nausea, fatigue, and non stop headaches, I haven't done any exercise in months, beyond walking to and from the train. It's not great (though luckily, my weight gain has been on target).

I'm hoping to get back into the gym and do most of my usual routine, but I'm wondering about what the best ab and core exercises are during pregnancy. I've noticed my abs feel... weird, when I just sit up from laying down, but it could be because literally my only exercise was dry heaving for a while. I'm only 16 weeks so I'm able to lay on my back without an issue so far, but that's probably going to end soon anyway.

What do other people do? I know it's so important to keep your core strong, I just have sucked at it lately!