Insensitive

My fiance always makes jokes about me being pregnant when he knows it is either too early or impossible. I am beyond tired of it probably out of frustration of failing for 9 months. I just hit my fertility window according to the calendar and I said my stomach was cramping and it was stiff which it is but I just had my period so we know I am not pregnant but he made a joke anyways. Now I am having severe lower back pain. Just frustrating knowing I am on cold medicine and I am not pregnant but due to my other medications I cannot even take something for my cramps or back. He jokes to brighten his mood. He wants a child as much as I do but he handles it differently than I do.