Monoclonal antibodies typically but not always have a risk of infusion related side effects. Just from the drug going in, but once in and past the first few days of possible effects from it doing it’s job, it should settle down. I have been familiar with a couple of them, one for myeloma (husband), and one for lung cancer (brother). Overwhelmingly they both had fatigue, and both required some level of anti nausea medicine.
Remember to report any side effects to your team, if it feels serious, do it immediately.
When are you due to start the new medicine?