MC Question

Rebecca • I`m 35yrs old, I have a 14yr old son.

I miscarried 9/26/18 and didn’t stop bleeding til 10/09/18. My question is I yet to receive my period and me and my fiancé have been trying again. What could be the reason my period hasn’t came back yet? I doubt it could be a new pregnancy or could it? I don’t want to test because I’m scared it’ll be a positive from the last pregnancy.