Getting worried about my 3 month old

I’m pretty sure I’ve written about this before but I’m started to get worried!

My baby’s startle/Moro reflex is not going away.

He gets startled in swing, activity gym, car seat..

he’ll fling his arms up and start crying! I notice he does it in the car seat when it’s dark outside mostly. He just gets so so scared it makes me so sad. He’s never done it in my arms or anything.

I showed his pediatrician and she said that it is perfectly normal, but I’m still worried!

Has anyone else experienced this? I’ve tried researching and don’t see any information. I’m at a loss..

I almost never leave my house in fear of him going it in his car seat because when he does, he cries hysterically until I take him out.

Also, I notice some days are worse than others.. I’m wondering if maybe it’s because he is swaddled at night and during naps, and doesn’t like the feeling of not being secure?? Idk... any help would be so appreciated!!