Should I contact my OB.??,

Okay lately I been having back pain & stomach cramps that’s on & off (I know round ligament pain) but last night i realized my baby girl is carrying really really low .. I feel my baby literally at my pubic bone shes really low at my belly

I’m on edge cause idk if that’s normal .. how really low she is . I’m 18 weeks & 1 day should I ask my doctor.?