Rapid weight gain!!

To start, I was at a normal BMI to start my pregnancy, but I was diagnosed with GD at 27 weeks. I feel like I've been doing great with my BS numbers. From 27-34 weeks I gained only 2 pounds (15 total). However this last two weeks, even with good blood sugar numbers and the same diet, I've jumped 5 pounds!! (Total gain of 20) Has this happened to anyone else?! I thought toward the end you stop gainin?! I'm so nervous they will want to induce me because of GD and that quick of weight gain.