Methotrexate

I'm going through a chemical pregnancy, my hcg numbers are low and increasing but slowly, about double every week. I had a d&c last week and the pathalogy report showed no placental villi. My number is still increasing. They want to give me a methotrexate injection, my doctor says theres no way the pregnancy will become viable. Has anyone had the injection?? It worries me what I read about it.