Overly worried?

I’ve never had any complications with pregnant or getting pregnant. Never had a miscarriage or anything.... i don’t know why, but with my first I wasn’t like this. With my second, I’m a worried freak. I had a 5 week ultrasound they thought I was 6 weeks, but all the saw was a sac and it was too early to see baby being only 5weeks. Now, I have an ultrasound next week when I’ll be a little over 7 weeks. What do I expect? I need to really calm my fears. I’ve had the perfect pregnancy so far, no bad sickness, no cramps, spotting nothing. Am I just being overly worried for no reason? I feel like I will stop once I hear the heartbeat