You have every right to be scared, with so many medications and especially when you hear that these are the cancer medications.
Although the medication Folitrex , which you call the cancer medication has a very important role in the management of rheumatoid arthritis
as well.It is called DISEASE MODIFYING ANTI RHEUMATIC MEDICATION,as the name suggests it actually modify the disease rather than simply giving pain relief. it is a very safe medication if used in recommended doses with regular monitoring.
Other Medications like calcium, vitamin D injections, iron , folic acid
etc are just supplements which can take without any harm for a prolong period.
Please do not get intimidated by the number of medications as they are all needed and are comparatively safer medications with a wider margin of safety.
Hope it helps, and Take Care.