I'm 39+3 weeks and for the last week or so I have this taste in my throat that gets worse when I'm laying flat down in…

I'm 39+3 weeks and for the last week or so I have this taste in my throat that gets worse when I'm laying flat down in bed but it's always there. It tastes almost like vomit, but its slightly sweet...I always feel like I'm going to throw up. The other night I woke up and there actually was a little bit of vomit in my mouth, unless it was saliva that just tasted that way...its really weird and I have no idea what it could be...do any of you have any ideas? I might have done a bad job describing it idk...