admitted to the hospital

As of today I am 34 weeks on the dot. Friday night I was having consistent contractions about 5 minutes apart so we came in for the 2nd time in two weeks. I have been in bed rest for preterm labor. I have been on magnesium since then and at midnight they took me off. Contractions have not returned to a regular pattern but are back. I was 2 cm and 80% effaced when I came in and had an intervaginal ultrasound that showed my cervix had shortened. I also had a positive ffn. The doc said about a 85-90 percent chance I'll be delivering this week and I am just freaking out. Any advise.