postpartum pain

I don't really know how to describe it but I am wondering if anyone knows what this is. I had my daughter almost 6 weeks ago (vaginally) and every couple days aince then I've been waking up with a horrible pain/pressure down there, but only when i sleep on my side. It almost feels like the pressure I had when her head was coming out. I haven't had sex yet and don't have my pp appointment till next week. Has amyone else had this or know what it is? it hurts to even get out of bed and walk to the bathroom, but goes away quickly after i stop laying on my side. tia