I gave birth in January and my 40 days are over I thought I started my period yesterday but white things come out with…

I gave birth in January and my 40 days are over I thought I started my period yesterday but white things come out with the blood and I just showered and a lot of blood came out has anyone gone thru this is it dangerous I've been cramping way to card all day and I've been feeling dizzy. when I finish peeing my vagina hurt not Burns and I can't poop or fart because it hurts way to much there too please help me