Loyal but uneasy customers are returning to the Haven Drugs in Medford, LI.

The pharmacy reopened Monday after it was shuttered following the Father’s Day massacre of four people there.

“I’ve been coming here for three years but I had to debate coming back. You visualize what happened,” said Maria Evrley , alluding to the coldblooded murders of four people allegedly by drug-crazed David Laffer.

“It broke my heart coming back here,” said Anthony Brennan, 51.