Methotrexate for ectopic pregnancy

K new grad here so I've got a few questions

I was recently informed that I will need to become chemo-certified for work so that I can give methotrexate for ectopic pregnancies and chemo to our pregnant patients with cancer. Has anyone ever been required to become chemo certified while working only on an OB floor? I guess I understand the reasoning but it still seems kind of strange and it makes me nervous because I feel like the chemo drugs are ones that we won't see very often but can still have some very major side effects.

I just started on that floor as a nurse but while in school also worked there as a NA. I remember about a year ago or so we had this patient receiving methotrexate and was complaining about significant pain so bad that she needed dilaudid to relieve it. What about administering this drug would cause such significant physical pain? I was looking it up today and saw that its also used to treat some autoimmune diseases (I think) so that didn't make sense.

I also remember another patient who had had several ectopic pregnancies...received methotrexate for the first two and then after that they removed the affected the fallopian tube. I was reading some info (I think on Medline) and it said that people taking methotrexate have a harder time getting pregnant. Is that why they would limit the doses? Or do you think that would only apply to people that take the drug on a regular basis?

Does anyone know of a good drug reference sheet or place I can find info on methotrexate specifically for ectopic pregnancies? Everything I find seems to be just general information on the drug and not what I am looking for.

Lastly, has anyone else given chemo to pregnant patients on their floor? I don't know how soon I'll be certified or if they'll even have me working with these patient in orientation (or if we'll even have one then), but if I had questions about this would I be better off asking them here or in the Oncology Forum?

Thanks in advance for help on ANY of this!