Periods a few days late

Alright, so, my period is a few days late and I'm freaking out about it. 
It was supposed to start on the 28th, but so far has shown no signs of coming. 
I haven't had sex that much - only two or three times this month, and I'm fairly sure I didn't have sex during my fertile window. 
Each time was unprotected, and I've been using the pullout method for months. 
I've recently started a new job, near my ovulation cycle, and I've changed my eating habits from eating one meal a day, to three. 
Is it likely that these changes could cause a delay? 
At what point should I start worrying about it? 
I'm 17, and I CANNOT have a child. My grandmother would kick me out if she knew I had sex. She's already kicked me out once for an unrelated reason, and she's said "YOU BETTER NOT COME HOME PREGNANT" to me a thousand times.
If I am pregnant, which I really hope I'm not, how could I.. "Take care" of it at home? 
Edit: I'm sorry if this is in the wrong board. I wasn't sure where to post it. Please correct me so I get the most effective help!