Ivf miscarriage

Please help me!!

I’ve recently had Ivf treatment 2 embryos transferred from frozen. I’ve hit positive tests and I’m 6 weeks pregnant.

This morning I had bad period like cramps and lower back aches with blood. The blood was bright red only when I wiped and has been on and off all day. I have a pad on and there’s no blood on my pad. I’ve contacted my clinic where I had my Ivf and all they’ve said is “ let nature take its cause”

Can anyone explain to me if I am miscarrying how long will I bleed for and how heavy would it be, also if you’ve bleed and then still been pregnant and gone onto have a healthy baby?!

Thanks