Missed five days in a summer school class where attendance counts?

I'm a freshman transfer and I'm taking PSC 101 during summer school (this term is five weeks). I left class early two days and I've missed like four days of class. On Thursday, my professor suggested that I not miss anymore class and I missed class today because I'm a commuter student and I live like 50 miles away from the university and the CAT bus was late and now I'm worried that I may fail this class because I've missed so many classes. My professor is really giving me a break but I don't know about this time. He may think that I'm lying and I really need to pass this class because it's one of my requirements for my major and my professor is the intern coordinator so I need to be on his good side. I'm really worried and I kind of don't know what to do. Please help me!