sick and pregnant

So I'm 26 weeks pregnant and I'm coming down with something and I feel really dehydrated so I'm going to make a dr appointment but my question is which dr do I call my primary or obgyn? I'm asking because the obgyn knows more of what I can and can't have. I just don't want to look stupid when I call but I do know I need to be seen in very afraid I'm dehydrated with being sick