Hello, Im 35 Years Old And Trying To Conceive. Presently

hello,
im 35 years old and trying to conceive. presently sailing with hubby and on folic , metformin 500 and neual for bp. i get severe knee pain once every month near my periods. due to poor diet on ship i fear lack of calcium , i need to know what calcium supplement can i take safely even if i conceive till i get back home and consult with my ob/gyn. also please guide me as to which drug is safe for the joint pain. i never take unless absilutely needed. thank you