miscarriage?

Me and my fiancé had unprotected sex (I usually take the pill but I was out and my prescription hadn't been refilled) two days before my period and now I'm on my third day of my period and I'm bleeding extremely hard. It's only 11 in the morning and I've already gone through 5 pads since 7am and they have been so full I was bleeding through them. I have had two previous miscarriage but I've never bled quite this bad. Just need some advice. I'm not sure if I might be having a miscarriage or if my body is just being weird. Advise please?!?