Submitted all my medical expenses not covered by the HSA but it looks like TurboTax is subtracting my HSA distributions from it. Why?

You need to also include in the medical-expense deduction section the amount of any medical expenses paid from the HSA, even if the HSA distribution was to reimburse yourself for medical expenses incurred in a prior year (but after the establishment of the HSA).  TurboTax automatically subtracts from your medical expenses entered in the medical-expense deductions section the amount of your HSA distribution that you indicated was spent on medical expenses.