Last night I got a light pink a little brownish discharge and it only lasted last night. I'm wondering what this could be. I ended my period 10 days ag?

Possible old blood. It might be old blood from your menstrual period that has "degenerated" and turned to brown. It can also be spotting from implantation bleeding or an injury post intercourse. Please check with your gyn if this continues.
Vaginal discharge. It might be a small clot of blood that was retained after your period, and which has slowly begun to dissolve. A thin, watery, brownish discharge is what you normal see in such situations. Other causes include rupture of small cysts in the vagina or cervix, friability (irritated surface) of the cervix, pelvic infection, or, in pregnancy states, an ectopic pregnancy or miscarriage.