Your cervix should be posterior, firm, and closed during pregnancy, so an open cervix means you have to rest to avoid complications or premature delivery.
You should not worry or panic. You will be subject to continuous monitoring by your obstetrician or midwife to prevent any risk of miscarriage or premature delivery. Doctor's orders,—rest!
You will have to limit your outings, avoid physical activities and lie down as much as possible to avoid contractions. Spa, nesting, preparation for the arrival of the baby... Make the most of this time to prepare everything and to be pampered!