False positive for syphilis

So I am in my 28th week of pregnancy so I had to do another set of blood work. My doctors nurse called to tell me that I tested positive for syphilis which is crazy to me because I took a test when I 1st found out I was pregnant and all came back negative plus I haven’t slept with anyone since then. But now she tell tells me they did another test and that one came back negative 😡. I’m confused I asked them how this could happen and they just told me some pregnant women can get false positives of syphilis. Has this happened to any other women because I still need answers