Don't feel bad. Last week was my 4th week as well and I couldn't make it to class because of my child as well. And to top it all off my group was presenting on Hygiene on Monday as well. I felt real bad because I didn't want my professor to think negative about me as well. So I call her that morning and explained to her my situation and she said ok. She moved the presentation to that Wednesday for my group and I didn't get penalized. So it will get better in time just as long as you don't make it a habit.