It is normal for pregnancy symptoms to come and go?

Brittany
Right now I'm 7w4days and for the last 3 days it seems like my pregnancy symptoms have slacked off. The nausea has returned but I'm still worried that something is really wrong. What I'm wondering is, is it normal for pregnancy symptoms to come and go? I've had one miscarriage before and it took me 4 years to conceive this baby.