I missed first period last Tuesday because I was sick early in the morning, all of last Thursday because I was up all night caring for my grandfather the night before, all of today because of his funeral, and then I’m thinking about not going tomorrow because I was really close to him and I’m still grieving and just don’t feel like I can handle the stress of my classes and talking to everyone right now. Besides, it’s homecoming and they’re having a big pep rally and dismissing early, so each class will be about 15 minutes, no actual teaching. That’s four absences in one class and three in all the others, all of them excused. This sounds like a lot for the first month!
However, I never miss any days in the second semester no matter what because if you have perfect attendance you can be exempt from finals. So I don’t plan on having any more than eight days total absent this year.
Is this too much?

yeah, it kinda is.
Depends on your state law, your schools policy in persueing such things, and how you are doing. In my last two years of high school I only showed up a few days a week and graduated at the top of my class, they never bothered me. On the other hand, If I missed a class a semester in college or grad school it was unusual.
Don’t worry about adding up absences for the year– you just lost your grandfather, you don’t need a pep rally right now, just a little space for grieving. Stay home.