Pink blood while nursing ?

I’ve been nursing my 6 months old since he was born. I also have a 18 month old. So I haven’t had a period in very long time. For the past two weeks my stomach has hurt and it’s been borderline unbearable. I’ve felt a little nauseous while driving too. Yesterday I used the bathroom and had a little bit of light pink blood. And a little bit more later that night. I threw a pad on but there’s nothing on the pad. I’ve had sex, and he’s pulled out, a total of like 6 times since the baby. Is it normal for this to happen while nursing or is there a chance I’m pregnant again?