Penicillin stomach pain

Hello all. I just recently finished a round of amoxicillin for a tooth abcess. And then 2 days ago I had a root canal and then my dentist put me on penicillin only after being off amox for 1 day. I have been having crappy stomach aches since I started the penicillin. I am taking a probiotic. Do I stop the penicillin and call my dentist? I already have a sensitive stomach and have IBSD. I am eating before I take the penicillin. So I dont know what to do.