Confused!!

Hello! I am very unsure of what to do! My period was expected almost 4 weeks ago. So far I have had nothing! I had a preterm birth and lost my baby in February at 23 weeks and hubby and I have been trying again! Last time I didn't show up positive on a test until I was 5 weeks! I have taken tests and so far all negative!! I have had so many symptoms and when I missed my period I was so sure I was!! I cant eat and I always feel nauseous like I did with my first pregnancy! I don't know what to do!! Should I call my provider or wait longer?!?