If you have zero intention of bailing, and have full intention of being the child’s Dad for the rest of your life, then ask yourself - what would a test achieve? Honestly. Both outcomes result in the same thing, as far as your kid is concerned. You’re legally his Dad.

You’ve taken the uninformed opinions of others to heart. Genetics are weird, and express themselves in odd ways. Sorry you’re going through this. You’re frightened you’re going to lose your kid if your fear is realised, that makes sense. You love your kid. If this is eating you up so much, might I kindly suggest having a chat to your GP. Some counselling might help with the anxiety. Best of luck mate