I Have Breast Cancer And Just Finished The First Half

I have breast cancer and just finished the first half of my scheduled 18 weeks of chemo therapy. I have been on lovenox until yesterday when I was taken off of it. Tonight I have quite a lot of bright red blood coming from my anus...I have had some diarrhea from the chemo so perhaps I have an internal hemorrhoid that is bleeding...should I call my doctor tonight or will it be okay until tomorrow? I am worried about internal bleeding.