Girls, who had low ferritin? How did you raise it? I'm 28 weeks pregna…

Girls, who had low ferritin? How did you raise it? I'm 28 weeks pregnant, I took a ferritin test, it was just at a minimal level (although hemoglobin is good. They said to do a ferinject drip. But I'm scared why? Who got it? Was there an effect? And how does iron deficiency affect the baby? (I'm worried now)