Fetal Monitoring at Hospital

Jina.
I'm 35+1 today and for the past two days I have been having more lower, abdominal cramps, back aches, and stomach tightening which I attributed to Braxton hicks. At work, today, I was miserable, in pain from so much tightening and tired. (I usually work an 8 hour day and on my feet for maybe 60% of my day). 
Went to my doctor's for a check up and they sent me to Labor & Delivery. They hooked me up to monitor my contractions and baby's heartbeat. I was having mild contractions every 6 mins😮. I had no idea. My husband kept asking me if I felt the contractions when he saw it on the monitor, and I couldn't. I just knew sometimes I was uncomfortable but they didn't feel like contractions! The dr checked me and I'm 70% effaced...they gave a shot called tributyline to stop the contractions which did for 45 mins. Since they didn't completely stop, I'm taking nifedipine (procardia) once a day for 6 days.  I was there from 3:30pm-6:45pm. 
I'm pretty tired now but glad baby was fine. Just have to keep him in there for at least 2 more weeks! 
Just wished I knew sooner to take it easy, since I can't tell at all that I was having not so good contractions.