It also depends on how far along you are too. If you're in your 1st trimester, your growing uterus has started to push in on your bladder. It gets better in the 2nd trimester, but returns in the 3rd trimester when baby's head is lower in your pelvis pushing on your bladder.
When you rest at night, that is when your kidneys will pull water that you have retained in your body throughout the day. From your legs and other extremidies. That is why you are peeing alot at night. Just start to cut down your water intake as the day goes on. Your going to have to pee more at night either way, but cutting back in the evening will help.