Symptoms gone??

I have had sore nipples for about 3 weeks and then my boobs started hurting about 3 days ago. This morning when I woke up nearly all of the pain was gone. I'm meant to be 6w4d according to this app and have my first US next Friday. I'm kind of concerned. This is my first pregnancy so I have no idea what to expect. No bleeding or cramps, just really really tired and nausea on and off but usually goes once I eat. Any thoughts??