short cervix...

Stevie • Married💍 11.24.18 3.26.17 👼🏼 EVR
I went to the doctor today for a check up. I've had on and off spotting the entire pregnancy (I'm 13w 2d) and at first he thought it was due to a polyp I had on my cervix. Then it stopped at 9 weeks and went away until about 12 weeks. Baby has always been fine, strong heart beat, dancing on ultrasounds.  I let  him know about the light spotting I had again and he decided to do another pelvic exam and said everything looked fine, then checked my cervix. He said he thought it was a little soft but he usually doesn't check a cervix this early on, so he sent me in for another ultrasound to get measurements. Turns out my cervix is a little shorter than it should be. He wants me to come back weekly to monitor, next week if nothing has changed he's putting me on medication and restrictions. He talked about later putting a stitch in my cervix if nothing changes. 
Has anyone had this or known anyone- experience, success?
Also sorry long post.. just concerned.