What is happening to me?!

Mary • 20 years old, engaged, mommy to a babygirl born on July 22nd, fur momma to my Yorkie-Poo, Zelda :)
My period just ended two weeks ago. Last night I had some spotting and thought it might have been implantation bleeding, but now I don't know. The blood only comes out if I am sitting on the toilet peeing and when I wipe. What could be going on?!