NST showed low FHR

Hi ladies. I had my second NST done this morning. (I’m scheduled to do them twice a week, Dr was concerned about cholestatis but labs came back normal) anyway in today’s NST the baby’s heart rate went down very low, twice. She was in the 180s-160s and it suddenly went down to 104. I felt and heard it on the monitor. I suddenly felt really weak and was sweating like a dog... has this happened to anyone else. We’re any of you induced? I’m at 38 weeks btw. TIA . I’m a little nervous just trying to relax. I have to go back again today to repeat the test.