Restlessness at night

I'm almost 18 weeks and already uncomfortable at night...I'm not even that big yet! I am constantly tossing and turning trying to get comfortable but I can't find a comfy sleeping position. It's like my muscles want me to get out of bed and stretch but I'm too tired to move. I keep waking my hubby up so I tend to go to our guest bedroom half way through the night. Guess it's good practice for not sleeping once baby gets here! Anyone else experiencing this? Any tips?