I get worried about my baby between prenatal appointments

I was initially really worried about a chemical or something going wrong in early pregnancy and was anxiously awaiting my first prenatal appointment, but after I saw it there in front of me on the ultrasound it helped it sink in that I was actually pregnant. I usually feel pretty confident in my pregnancy especially for a while after my appointments but then about two weeks go by and I start to get worried again for a minute! It just feels like so long to go between without hearing his heartbeat or confirming he’s okay. I’m now 17 weeks and haven’t felt any movements yet and my next appointment is 3 weeks away and I’m just nervous again! I just want him to be okay. And I’m sure I’ll get comments like “oh don’t stress it’s bad for the baby think positive” and I usually do, I’m not a person with a lot of stress or anxiety so that’s not a problem. I just every once in a while get emotional about him and my heart hurts thinking about him not being okay