Should I call my ob?

I'm 11 weeks today. I noticed on Friday I had a very small amount of pink tinged discharge. It's been on and off since then. Today it appeared to stop. I just woke up from a nap and went to the bathroom and I noticed when I wiped it was all a very light pink. I dont have any cramping. However, I am B- so im unsure if that has anything to do with it. I have an appointment on Tuesday morning. I do have a 12 hour shift tomorrow. Should I call and see what they say or just monitor and make sure it doesn't get darker?