Vanishing symptoms? Experienced moms please help!

According to this app, I am almost 7 weeks pregnant. For the last few days I've noticed that most of my symptoms have vanished. I never had bad morning sickness that caused me to vomit, but I did have mild to medium nausea depending on the day. I also felt severely fatigued, bloated, constipated, gassy, and would pee frequently. Now the only symptom I really have is sore breasts. I'm not waking up multiple times in the middle of the night to go pee anymore.
This is my first pregnancy and I'm really worried. My first ultrasound appointment isn't for another few weeks. I feel this is too early for me to be losing symptoms unless something is wrong. I'm not experiencing any cramping or spotting, so I know that's a good sign, but the disappearance of my other symptoms is what scares me.
Has this happened to any of you before and you ended up having a healthy pregnancy and baby? Is it common for symptoms to come and go or to end so early without it meaning there's a problem?