Lower abdomen pain, 16 days late, pregnant?

[emanueleclipse]

So, I"m really hoping I could get some advice or even answers.

I'm 16 days late and I usually get my cycle somewhat regularly, Me and my boyfriend use the "withdrawal method".
I heard that pre-*** can get you pregnant. (I'm aware of the chances of pregnancy.)

I've been experiencing low back pain and this random sharp pain on my lower right side of my abdomen. It'll hurt for a few seconds and then stop. (on and off) I'm nauseous randomly almost all day, especially in the morning. I've had these weird headaches that don't go away with meds or even sleep. I'm always tired. My ovulation date was july 6, I'm still waiting on my period, I'm not sure when to test. I'm tired of feeling all achy and just blah, I want to know what's going on, so any feedback or advice would be very helpful. I have a test, just waiting on when to take it.