Why taxes seem to go up when entering 1099-SA and no HDHP in 2019?

I entered my 1099-SA in TurboTax and the tax I owe seemed to go up, which surprised me because I used my HSA to pay ONLY health care expenses.  I had a high-deductible-health-plan (HDHP) in 2018, when I contributed to my HSA, but I did not have a HDHP in 2019 and did not contribute to my HSA.  
If I use my HSA to pay for health care expenses in a year in which I didn't have a HDHP, do I pay taxes on what I spent?