Very confused, HELP!

I've been on the pill since September. My October period came early even though I was on the pill and even though my next period isn't until 12 days from now, (11/10) according to this app, my body has felt off the past week or so. My breast are tender, my stomach has been feeling tight, I've been very fatigued even with lots of sleep. Is it possible to get pregnant while on the pill? I've had a few social events recently, especially on my ovulation dates according to this app, and I read alcohol decreases the rate of absorption from the pill. My SO and I have sex almost daily. Is it too early to test? Should I just wait until my period? They say women can feel it and I'm feeling something.