Medication making symptoms worse

I’ve been given Lansoprazole and Famotidine, the Famotidine I initially found to be more beneficial than the Lansoprazole but I’ve read you’re not meant to be on it longer than 14 days. I’ve also found with both my symptoms are worse than ever. I’ve lost my appetite, I’m nauseous all the time, really dizzy, classic burning symptoms, lump in my throat etc. I don’t know what to do, is it better to stop using the medications but then I know it can get even worse for a bit, how long does it take to calm down again?