Ceftriaxone Pulse Dose for Post-Treatment Lyme Disease

The goal of this clinical trial is to learn if an FDA approved drug, Ceftriaxone, given intermittently, can treat people between 18 and 75 years old with a history of Lyme disease, who are still experiencing persistent or returning symptoms after they have completed treatment. The main questions it aims to answer are: * Will giving Ceftriaxone approximately every 5 days for 6 weeks be safe and well tolerated when compared to a group that receives placebo (a look-alike substance that contains no drug)? * Will giving Ceftriaxone improve symptoms? Participants will be asked to do the following: * Come to the clinic approximately every 5-6 days to receive an IV infusion of either the Ceftriaxone or placebo. * Answer questions about their level of tiredness, body pain, general health and physical ability, sleep, anxiety, depression and any suicidal thoughts. * Give blood so we can make sure your body is handling the drug okay or to help us learn more about how the drug is affecting the persistent Lyme disease symptoms.