Location Of Cervix Before Menstruation Placenta Covering/touching My Cervix...?

Placenta covering/touching my cervix...? - location of cervix before menstruation

Hello! I am 18 weeks with baby # 3 I had a routine application. Tuesday and started spotting (brown, not red) in the evening. I went to the doc on Wednesday and they made a noise. Said it seemed that my placenta is covering / touching part of my neck. He examined me and my cervix is closed. He put in a reduced activity (thank God was total bed rest!) And told me to act like a tramp. However, when I get up, because I feel a little pressure. Now I understand that in 18 weeks, my baby is too small to be the cause of this pressure, but do you think could be due to the location of the placenta? I understand that there is a possibility that my placenta can move, growing up my uterus, and could end with a vagainal delivery, but what if not? Did you keep your placenta, where he (the cervix), and a caesarean? The doctor might not seem too worried. He only said he will see me close. But I'm a little nervous ...