Can you tell me how to know if i'm having a miscarriage or an ectopic pregnancy?

Its complicated: Telling the difference between an ectopic pregnancy and a miscarriage in early pregnancy can be challenging, even for your Ob/Gyn. Pain on one side of your lower abdomen, associated with bleeding is worrisome for an ectopic. Sometimes its impossible to know without performing ultrasounds and HCG blood levels each week for several weeks. Best to let a doc with experience handle it.