I’m 34 weeks still measuring small

When I was 29 weeks I was measuring 28 which was normal. Now im 34 weeks and measuring 29 weeks. Im super worried the doctors arnt really saying much. Now I’ve been diagnosed with being anemic. Im gaining weight but I don’t think my baby is. Has anyone been through this? What can I do? Im worried!! The kicks are strong and every one of my appointments they say her heartbeat is beautiful. Also having pain when walking to long in my pelvic area and under stomach