Am I getting the Swine Flu?

Okay I'm 15 and my little sister has swine flu bad, and I've been in the same house as her for about a week so I'm pretty sure I'm going to get it. I've been feeling very tired and had a head ache for about 2 days now and I had a 99.5 fever yesterday but now it's back down to normal. I don't know if I should go to school tomorrow or not, my mom says it takes about 5 days for it to show symptoms, I don't want to go to school and spread it, am I getting it? I slept 12 hours each night the past 2 nights and woke up with dark circles under my eyes.