Is it ok to call off work sometimes?

[Emily]

I've worked at my employer (a nationally known retail store) for over a year and a half now and I've never called off ever while others call off all the time. We have this credit system that if you don't show up or come late it takes points away, but if you're on time every shift for a month you gain a credit. I currently have 18, which is the maximum they allow you to accumulate because I've never called off or have been late.

But I am just so sick and tired of them scheduling me terrible shifts this christmas season and scheduling the seasonal workers the daytime shifts! I feel like as a year round associate I should at least deserve one daytime shift a week instead of all these early morning and overnight shifts. So far I've had to miss my high school youth group's reunion and a christmas party because of my shifts, but now I'm scheduled during my close friends' christmas party! My shift, on a Sunday night, is from 2 in the afternoon until 12 midnight!! I feel like my job (which isn't even a permanent job; I'm a full-time student as well) is overtaking my life and causing me to have no social life.

I'm just so unbelievably frustrated right now. I'm considering calling off. I know it won't affect me at all because I'll only lose two points out of my 18. But I just feel bad because I don't like to leave them without help.

What should I do? do you think it would be ok to call off this one time?