Low Calcium on Denosumab

I’m on my chemo phase for mets to bones and liver - Pertuzumab, Trastuzumab, Docetaxol every 3 weeks - had 5/6
Been having Denusomab injections every 6weeks . My calcium levels have dropped and I couldn’t have it this time - been told I need to build them up before I can continue.
Also taking Exemestane.
My question is - has this happened to you and how long does it take to get calcium levels back up?
Thanks