Discomfort While Standing, Fine When Laying Down 17 Weeks

So ladies I’m 17 weeks with my second and it has been relatively easy so far.

However for the past few days, every time I’m on my feet for more than 10 minutes I get this discomfort in my stomach and terrible nausea. Sitting doesn’t alleviate it at all, only laying down.

I don’t want to just call my doctor for anything but it’s getting more and more uncomfortable and I’m starting to get concerned.

Has anyone else ever had anything like this?