Idk what to do

So long story short, I quit taking the pill about a month ago to switch to the Nuva ring and my OBGYN said to put it in the Sunday after I start my period. Well I never started my period. I’m 8 days late and I’ve tested a couple times but all negative. My fiancé and I were sort of trying to conceive during that period of time and well I just don’t know what to do. Tonight I have some serious cramping on my left lower abdominal/ovary area and with a heating pad I felt better but I haven’t started my period. When should I test again? Has anyone been through this?