I had my first Reclast infusion May 12, 2025. I hydrated the day before, the day of and the day after the infusion. I've had no side effects whatsoever. My infusion nurse told me that they have only had patients report mild flu-like symptoms and no other side-effects in the three years she's been administering Reclast. I know that some people do experience side effects, but it's been in use for 18 years and has extensive data. I find that reassuring.
Aside from hydrating to protect your kidneys, I would say that a trip to the dentist is a good idea. You probably already know that you can't have invasive dental work for a minimum of one year after Reclast.
Staying positive is a choice I've embraced as living in fear is stressful and unhealthy. I've done that already and I refuse to go back! So far I've done Fosamax, Evenity, Tymlos and Reclast. Best wishes to you!