Please give advice: Down’s syndrome

We done a private nipt test at 10w5d (first baby) which is basically a harmony test to check any abnormalities in your child. Everything came back fine with all low probability, 1 in 10000) I then got the testing on the nhs at 12w6d and they have told me that test came back as 1 in 105 chance for Down’s syndrome. I’m so confused and so scared. I’m now 15 weeks Which should I trust more? I’m so scared to get further testing. I also feel like if anything is wrong with my baby it’s my fault as I have hypothyroidism and at one point it went untreated for a week and my levels went to 15. But my levels are back in normal range now. If my baby doesn’t have Down’s syndrome I’m terrified that maybe he has something worse and that could be the reason the nhs testing says 1 in 105. Please give any advice or words of encouragement. I’m so scared.