Is it too early?

Hi 18 F, I have recently been having unprotected sex with my new partner. We’ve had unprotected sex for most of last week probably like five days. I had just ended my period a few days earlier and now I’m bleeding again. It’s a heavy flow like a period but it’s not the consistency of period blood. It’s also not pink or brown. It’s the color of period blood as well. I also have very tender breast and feel very nauseous but it’s only been four or five days since we first had unprotected sex, I also took a plan B after the second time but now I’m just worried now, would pregnancy symptoms happen this early?