31 weeks, not feeling right.

I'm 31 weeks and 2 days today. I've had a few bouts of dizziness during this pregnancy and have usually been able to reduce it with water and a snack. Today I've been feeling really off. I have a dull but obnoxious headache, I'm feeling very dizzy and am occasionally seeing stars both when I sit and stand, I feel kind of nauseous, my arms feel very weak and heavy, and I feel anxious and it feels like it's hard to breathe. I've called my doctor but had to leave a message and am waiting to get a call back. I've been drinking a ton of water.  I'm a ftm and have gone to the ER before for small things that I was just over worried about and don't really want to go if it's another "false alarm". Has anyone else experienced this? Should I go to the doctors? The ER? Or am I overreacting again?