3 steps forward, 1 step back

This pregnancy is getting to me more than being pregnant with Graham.  Part of it is undoubtedly related to my level of excitement being different in the 2 pregnancies.  I was so over the moon thrilled to be pregnant with Graham, I may have just overlooked all the aches and pains. But I'm feeling them with this one. Now that I've made it through the first trimester, I will have 2 or 3 good days, where I have decent energy and little physical discomfort, which are then followed by a day where I'm tired, and I ache, and I'm cranky. Which about sums up how I feel tonight.  I find myself wondering, if I'm this achy at 18 weeks, how will I feel as this pregnancy progresses?