Crazy high numbers all of a sudden

I've been testing my glucose for about 3 weeks now, and the first two weeks all my numbers looked really good...80s-90s after meals and lower than that for fasting. Well, this week (I'm now 31 weeks) my fasting numbers have been really high and my non fasting are not over the threshold, but they're much higher (low to mid 100s). Has anyone else experienced this where they are able to maintain good numbers with diet then suddenly they can't anymore? My specialist said that as baby and placenta get bigger more of the hormone is secreted that causes GD so it gets harder to manage, I just didn't think it would switch that quickly. I think taking meds is in my immediate future.