Is this an infection or nothing at all.?

I was feeling a bit nauseated yesterday and puked later. I am 27 weeks pregnant so I am uming it had something to do with it. But I can also feel a little dry and slightly congested in my throat/chest/neck. My throat was really sore when I woke up this morning but has subsided pretty much. It is a little sore but not too bad. But I looked at the back of my mouth and I have this large white spot and some redness. Is this the beginning of an infection or should I just wait till it gets worse to go see the doc?