Your urination habits can vary based on the amount of water you drink. Also, if you ate really salty food last night, that can cause you to retain the fluid instead of urinating as much out. Make sure you are drinking plenty of water. Your uterus is also growing upward, which can alleviate some of the pressure. Variations are normal though. If you are drinking plenty of water and still not urinating much, then you should call your doctor. You may find that your evening urination habits return to normal tonight. You may have also been extra tired and slept through the urge to urinate.
Its possible you just drank less those past couple hours. Or it might be that your uterus shifted slightly away from your bladder so it isn't pressing on it so hard. If this goes on and you're still drinking a lot of water, and you feel dehydrated, go to your doctor, but for now just drink lots of fluids, and enjoy not having to rush to the bathroom!