Anyone else?

So today I'm 35 weeks, and went to my check up and they had a hard time finding my daughter heart beat but finally found it, it wasn't as strong as my doctor wanted (HR 135 normally 145 150), so she wanted to hook me up to the non stress test to monitor her for 40 mins, she passed. But after it was done my doc told me I was having some contractions (back) she is facing my back so I'll have back labor again (had it with my son) I have had some lower back pain today but it makes me nervous since last time I was in labor I didn't think I was since it was just back pains luckily I went into hospital just in case and had my son within a hr. It was to close! I didn't feel them when they were coming up on the monitor so my doctor just told me if I start feeling them and they hurt to come to hospital. Has anyone else had this happen? Did you end up giving birth early?