Can symptoms come and go?

ItsGoingToWorkOut

Today I'm 7w 2d and during my ultrasound the other day my RE confirmed we have twins, with heart rates of 121 and 119; however, they measured 6w4d and 6w2d. He said to not worry about the size because it was "within range," but since then my breasts no longer feel tender, I'm not as fatigued and my face has cleared up. Is it norma for these symptoms to come and go? I feel "too normal" if that makes any sense. We've had six miscarries, none going longer than 10 weeks, and this was our first IVF, so we're just anxious to make sure these little guys work. 

Guidance to help ease my nerves would be great. Thanks!!