Thanks for the query.
As you are having Turners syndrome and on HRT
there is less chance of pregnancy
you are having may be because of stopping the HRT.
You didn't mention whether your previous pregnancies ended successfully or not.
Sometimes urine pregnancy test kits can give false positive results.
So you better go for blood test
for pregnancy which will give accurate result.
If the test comes negative again you may have to start HRT to get periods with your doctor's advice.