I am now in my 18weeks, i feel like im having a cramping in my tummy. Is it normal? Help me mumsh😥

19 weeks po ako nung mpansin ko na parang sumakit yung tyan ko more than an hour 2x nangyari diffent days. then Nung check up sched ko nakita sa ultrasound na may contraction daw po sa loob ng tyan. Nagreseta ng gamit c OB. Better po pacheck up mo po sis.