Sleep escapes me!

I don't know what it is about pregnancy that causes me to be this way but I am so tired of not being able to sleep the whole night through. I'm so exhausted! Last night was a typical night of waking up every three or four hours, usually from some ridiculous dream where I was working as a hair stylist or cleaning the upholstry on the furniture. I don't think the dog is sleeping very well either (she insists on sleeping right up next to my back) because of my tossing turning. I've tried different pillows,different configurations of pillows, taking naps and not taking naps. I don't drink caffeine often and never past noon. I long for the days when the baby is here and not a second of interrupted sleep is wasted on dreams. I know I was tired after little boy came home but I wasn't frustrated! I dread bed time because I know it will just be another night of crazy dreams and waking up grouchy and tired. Anybody have any suggestions other than Tylenol PM?