Uy mama, this is something na kailangan talaga ng doctor to check ASAP, don't wait, please go to your OB or emergency room kung available ngayon pa lang. An open cervix during pregnancy needs proper medical care and monitoring, hindi ito something na ma-handle lang sa bahay.
Alam ko nakakatakot ang ganito lalo na first time, pero ang best thing you can do is get to your doctor right away para malaman nila exactly kung ano ang nangyayari at ano ang safest plan para sa iyo at sa baby. Praying for you, sis, update us when you can.